SemaChecking.cpp revision ab4702febef82409773f7c80ec02d53ddbb4d80e 
1//===--- SemaChecking.cpp - Extra Semantic Checking -----------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10//  This file implements extra semantic analysis beyond what is enforced
11//  by the C type system.
12//
13//===----------------------------------------------------------------------===//
14
15#include "clang/Sema/Initialization.h"
16#include "clang/Sema/Sema.h"
17#include "clang/Sema/SemaInternal.h"
18#include "clang/Sema/Initialization.h"
19#include "clang/Sema/Lookup.h"
20#include "clang/Sema/ScopeInfo.h"
21#include "clang/Analysis/Analyses/FormatString.h"
22#include "clang/AST/ASTContext.h"
23#include "clang/AST/CharUnits.h"
24#include "clang/AST/DeclCXX.h"
25#include "clang/AST/DeclObjC.h"
26#include "clang/AST/Expr.h"
27#include "clang/AST/ExprCXX.h"
28#include "clang/AST/ExprObjC.h"
29#include "clang/AST/EvaluatedExprVisitor.h"
30#include "clang/AST/DeclObjC.h"
31#include "clang/AST/StmtCXX.h"
32#include "clang/AST/StmtObjC.h"
33#include "clang/Lex/Preprocessor.h"
34#include "llvm/ADT/BitVector.h"
35#include "llvm/ADT/SmallString.h"
36#include "llvm/ADT/STLExtras.h"
37#include "llvm/Support/raw_ostream.h"
38#include "clang/Basic/TargetBuiltins.h"
39#include "clang/Basic/TargetInfo.h"
40#include "clang/Basic/ConvertUTF.h"
41#include <limits>
42using namespace clang;
43using namespace sema;
44
45SourceLocation Sema::getLocationOfStringLiteralByte(const StringLiteral *SL,
46                                                    unsigned ByteNo) const {
47  return SL->getLocationOfByte(ByteNo, PP.getSourceManager(),
48                               PP.getLangOpts(), PP.getTargetInfo());
49}
50
51/// Checks that a call expression's argument count is the desired number.
52/// This is useful when doing custom type-checking.  Returns true on error.
53static bool checkArgCount(Sema &S, CallExpr *call, unsigned desiredArgCount) {
54  unsigned argCount = call->getNumArgs();
55  if (argCount == desiredArgCount) return false;
56
57  if (argCount < desiredArgCount)
58    return S.Diag(call->getLocEnd(), diag::err_typecheck_call_too_few_args)
59        << 0 /*function call*/ << desiredArgCount << argCount
60        << call->getSourceRange();
61
62  // Highlight all the excess arguments.
63  SourceRange range(call->getArg(desiredArgCount)->getLocStart(),
64                    call->getArg(argCount - 1)->getLocEnd());
65
66  return S.Diag(range.getBegin(), diag::err_typecheck_call_too_many_args)
67    << 0 /*function call*/ << desiredArgCount << argCount
68    << call->getArg(1)->getSourceRange();
69}
70
71/// Check that the first argument to __builtin_annotation is an integer
72/// and the second argument is a non-wide string literal.
73static bool SemaBuiltinAnnotation(Sema &S, CallExpr *TheCall) {
74  if (checkArgCount(S, TheCall, 2))
75    return true;
76
77  // First argument should be an integer.
78  Expr *ValArg = TheCall->getArg(0);
79  QualType Ty = ValArg->getType();
80  if (!Ty->isIntegerType()) {
81    S.Diag(ValArg->getLocStart(), diag::err_builtin_annotation_first_arg)
82      << ValArg->getSourceRange();
83    return true;
84  }
85
86  // Second argument should be a constant string.
87  Expr *StrArg = TheCall->getArg(1)->IgnoreParenCasts();
88  StringLiteral *Literal = dyn_cast<StringLiteral>(StrArg);
89  if (!Literal || !Literal->isAscii()) {
90    S.Diag(StrArg->getLocStart(), diag::err_builtin_annotation_second_arg)
91      << StrArg->getSourceRange();
92    return true;
93  }
94
95  TheCall->setType(Ty);
96  return false;
97}
98
99ExprResult
100Sema::CheckBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) {
101  ExprResult TheCallResult(Owned(TheCall));
102
103  // Find out if any arguments are required to be integer constant expressions.
104  unsigned ICEArguments = 0;
105  ASTContext::GetBuiltinTypeError Error;
106  Context.GetBuiltinType(BuiltinID, Error, &ICEArguments);
107  if (Error != ASTContext::GE_None)
108    ICEArguments = 0;  // Don't diagnose previously diagnosed errors.
109
110  // If any arguments are required to be ICE's, check and diagnose.
111  for (unsigned ArgNo = 0; ICEArguments != 0; ++ArgNo) {
112    // Skip arguments not required to be ICE's.
113    if ((ICEArguments & (1 << ArgNo)) == 0) continue;
114
115    llvm::APSInt Result;
116    if (SemaBuiltinConstantArg(TheCall, ArgNo, Result))
117      return true;
118    ICEArguments &= ~(1 << ArgNo);
119  }
120
121  switch (BuiltinID) {
122  case Builtin::BI__builtin___CFStringMakeConstantString:
123    assert(TheCall->getNumArgs() == 1 &&
124           "Wrong # arguments to builtin CFStringMakeConstantString");
125    if (CheckObjCString(TheCall->getArg(0)))
126      return ExprError();
127    break;
128  case Builtin::BI__builtin_stdarg_start:
129  case Builtin::BI__builtin_va_start:
130    if (SemaBuiltinVAStart(TheCall))
131      return ExprError();
132    break;
133  case Builtin::BI__builtin_isgreater:
134  case Builtin::BI__builtin_isgreaterequal:
135  case Builtin::BI__builtin_isless:
136  case Builtin::BI__builtin_islessequal:
137  case Builtin::BI__builtin_islessgreater:
138  case Builtin::BI__builtin_isunordered:
139    if (SemaBuiltinUnorderedCompare(TheCall))
140      return ExprError();
141    break;
142  case Builtin::BI__builtin_fpclassify:
143    if (SemaBuiltinFPClassification(TheCall, 6))
144      return ExprError();
145    break;
146  case Builtin::BI__builtin_isfinite:
147  case Builtin::BI__builtin_isinf:
148  case Builtin::BI__builtin_isinf_sign:
149  case Builtin::BI__builtin_isnan:
150  case Builtin::BI__builtin_isnormal:
151    if (SemaBuiltinFPClassification(TheCall, 1))
152      return ExprError();
153    break;
154  case Builtin::BI__builtin_shufflevector:
155    return SemaBuiltinShuffleVector(TheCall);
156    // TheCall will be freed by the smart pointer here, but that's fine, since
157    // SemaBuiltinShuffleVector guts it, but then doesn't release it.
158  case Builtin::BI__builtin_prefetch:
159    if (SemaBuiltinPrefetch(TheCall))
160      return ExprError();
161    break;
162  case Builtin::BI__builtin_object_size:
163    if (SemaBuiltinObjectSize(TheCall))
164      return ExprError();
165    break;
166  case Builtin::BI__builtin_longjmp:
167    if (SemaBuiltinLongjmp(TheCall))
168      return ExprError();
169    break;
170
171  case Builtin::BI__builtin_classify_type:
172    if (checkArgCount(*this, TheCall, 1)) return true;
173    TheCall->setType(Context.IntTy);
174    break;
175  case Builtin::BI__builtin_constant_p:
176    if (checkArgCount(*this, TheCall, 1)) return true;
177    TheCall->setType(Context.IntTy);
178    break;
179  case Builtin::BI__sync_fetch_and_add:
180  case Builtin::BI__sync_fetch_and_add_1:
181  case Builtin::BI__sync_fetch_and_add_2:
182  case Builtin::BI__sync_fetch_and_add_4:
183  case Builtin::BI__sync_fetch_and_add_8:
184  case Builtin::BI__sync_fetch_and_add_16:
185  case Builtin::BI__sync_fetch_and_sub:
186  case Builtin::BI__sync_fetch_and_sub_1:
187  case Builtin::BI__sync_fetch_and_sub_2:
188  case Builtin::BI__sync_fetch_and_sub_4:
189  case Builtin::BI__sync_fetch_and_sub_8:
190  case Builtin::BI__sync_fetch_and_sub_16:
191  case Builtin::BI__sync_fetch_and_or:
192  case Builtin::BI__sync_fetch_and_or_1:
193  case Builtin::BI__sync_fetch_and_or_2:
194  case Builtin::BI__sync_fetch_and_or_4:
195  case Builtin::BI__sync_fetch_and_or_8:
196  case Builtin::BI__sync_fetch_and_or_16:
197  case Builtin::BI__sync_fetch_and_and:
198  case Builtin::BI__sync_fetch_and_and_1:
199  case Builtin::BI__sync_fetch_and_and_2:
200  case Builtin::BI__sync_fetch_and_and_4:
201  case Builtin::BI__sync_fetch_and_and_8:
202  case Builtin::BI__sync_fetch_and_and_16:
203  case Builtin::BI__sync_fetch_and_xor:
204  case Builtin::BI__sync_fetch_and_xor_1:
205  case Builtin::BI__sync_fetch_and_xor_2:
206  case Builtin::BI__sync_fetch_and_xor_4:
207  case Builtin::BI__sync_fetch_and_xor_8:
208  case Builtin::BI__sync_fetch_and_xor_16:
209  case Builtin::BI__sync_add_and_fetch:
210  case Builtin::BI__sync_add_and_fetch_1:
211  case Builtin::BI__sync_add_and_fetch_2:
212  case Builtin::BI__sync_add_and_fetch_4:
213  case Builtin::BI__sync_add_and_fetch_8:
214  case Builtin::BI__sync_add_and_fetch_16:
215  case Builtin::BI__sync_sub_and_fetch:
216  case Builtin::BI__sync_sub_and_fetch_1:
217  case Builtin::BI__sync_sub_and_fetch_2:
218  case Builtin::BI__sync_sub_and_fetch_4:
219  case Builtin::BI__sync_sub_and_fetch_8:
220  case Builtin::BI__sync_sub_and_fetch_16:
221  case Builtin::BI__sync_and_and_fetch:
222  case Builtin::BI__sync_and_and_fetch_1:
223  case Builtin::BI__sync_and_and_fetch_2:
224  case Builtin::BI__sync_and_and_fetch_4:
225  case Builtin::BI__sync_and_and_fetch_8:
226  case Builtin::BI__sync_and_and_fetch_16:
227  case Builtin::BI__sync_or_and_fetch:
228  case Builtin::BI__sync_or_and_fetch_1:
229  case Builtin::BI__sync_or_and_fetch_2:
230  case Builtin::BI__sync_or_and_fetch_4:
231  case Builtin::BI__sync_or_and_fetch_8:
232  case Builtin::BI__sync_or_and_fetch_16:
233  case Builtin::BI__sync_xor_and_fetch:
234  case Builtin::BI__sync_xor_and_fetch_1:
235  case Builtin::BI__sync_xor_and_fetch_2:
236  case Builtin::BI__sync_xor_and_fetch_4:
237  case Builtin::BI__sync_xor_and_fetch_8:
238  case Builtin::BI__sync_xor_and_fetch_16:
239  case Builtin::BI__sync_val_compare_and_swap:
240  case Builtin::BI__sync_val_compare_and_swap_1:
241  case Builtin::BI__sync_val_compare_and_swap_2:
242  case Builtin::BI__sync_val_compare_and_swap_4:
243  case Builtin::BI__sync_val_compare_and_swap_8:
244  case Builtin::BI__sync_val_compare_and_swap_16:
245  case Builtin::BI__sync_bool_compare_and_swap:
246  case Builtin::BI__sync_bool_compare_and_swap_1:
247  case Builtin::BI__sync_bool_compare_and_swap_2:
248  case Builtin::BI__sync_bool_compare_and_swap_4:
249  case Builtin::BI__sync_bool_compare_and_swap_8:
250  case Builtin::BI__sync_bool_compare_and_swap_16:
251  case Builtin::BI__sync_lock_test_and_set:
252  case Builtin::BI__sync_lock_test_and_set_1:
253  case Builtin::BI__sync_lock_test_and_set_2:
254  case Builtin::BI__sync_lock_test_and_set_4:
255  case Builtin::BI__sync_lock_test_and_set_8:
256  case Builtin::BI__sync_lock_test_and_set_16:
257  case Builtin::BI__sync_lock_release:
258  case Builtin::BI__sync_lock_release_1:
259  case Builtin::BI__sync_lock_release_2:
260  case Builtin::BI__sync_lock_release_4:
261  case Builtin::BI__sync_lock_release_8:
262  case Builtin::BI__sync_lock_release_16:
263  case Builtin::BI__sync_swap:
264  case Builtin::BI__sync_swap_1:
265  case Builtin::BI__sync_swap_2:
266  case Builtin::BI__sync_swap_4:
267  case Builtin::BI__sync_swap_8:
268  case Builtin::BI__sync_swap_16:
269    return SemaBuiltinAtomicOverloaded(TheCallResult);
270#define BUILTIN(ID, TYPE, ATTRS)
271#define ATOMIC_BUILTIN(ID, TYPE, ATTRS) \
272  case Builtin::BI##ID: \
273    return SemaAtomicOpsOverloaded(TheCallResult, AtomicExpr::AO##ID);
274#include "clang/Basic/Builtins.def"
275  case Builtin::BI__builtin_annotation:
276    if (SemaBuiltinAnnotation(*this, TheCall))
277      return ExprError();
278    break;
279  }
280
281  // Since the target specific builtins for each arch overlap, only check those
282  // of the arch we are compiling for.
283  if (BuiltinID >= Builtin::FirstTSBuiltin) {
284    switch (Context.getTargetInfo().getTriple().getArch()) {
285      case llvm::Triple::arm:
286      case llvm::Triple::thumb:
287        if (CheckARMBuiltinFunctionCall(BuiltinID, TheCall))
288          return ExprError();
289        break;
290      case llvm::Triple::mips:
291      case llvm::Triple::mipsel:
292      case llvm::Triple::mips64:
293      case llvm::Triple::mips64el:
294        if (CheckMipsBuiltinFunctionCall(BuiltinID, TheCall))
295          return ExprError();
296        break;
297      default:
298        break;
299    }
300  }
301
302  return TheCallResult;
303}
304
305// Get the valid immediate range for the specified NEON type code.
306static unsigned RFT(unsigned t, bool shift = false) {
307  NeonTypeFlags Type(t);
308  int IsQuad = Type.isQuad();
309  switch (Type.getEltType()) {
310  case NeonTypeFlags::Int8:
311  case NeonTypeFlags::Poly8:
312    return shift ? 7 : (8 << IsQuad) - 1;
313  case NeonTypeFlags::Int16:
314  case NeonTypeFlags::Poly16:
315    return shift ? 15 : (4 << IsQuad) - 1;
316  case NeonTypeFlags::Int32:
317    return shift ? 31 : (2 << IsQuad) - 1;
318  case NeonTypeFlags::Int64:
319    return shift ? 63 : (1 << IsQuad) - 1;
320  case NeonTypeFlags::Float16:
321    assert(!shift && "cannot shift float types!");
322    return (4 << IsQuad) - 1;
323  case NeonTypeFlags::Float32:
324    assert(!shift && "cannot shift float types!");
325    return (2 << IsQuad) - 1;
326  }
327  llvm_unreachable("Invalid NeonTypeFlag!");
328}
329
330/// getNeonEltType - Return the QualType corresponding to the elements of
331/// the vector type specified by the NeonTypeFlags.  This is used to check
332/// the pointer arguments for Neon load/store intrinsics.
333static QualType getNeonEltType(NeonTypeFlags Flags, ASTContext &Context) {
334  switch (Flags.getEltType()) {
335  case NeonTypeFlags::Int8:
336    return Flags.isUnsigned() ? Context.UnsignedCharTy : Context.SignedCharTy;
337  case NeonTypeFlags::Int16:
338    return Flags.isUnsigned() ? Context.UnsignedShortTy : Context.ShortTy;
339  case NeonTypeFlags::Int32:
340    return Flags.isUnsigned() ? Context.UnsignedIntTy : Context.IntTy;
341  case NeonTypeFlags::Int64:
342    return Flags.isUnsigned() ? Context.UnsignedLongLongTy : Context.LongLongTy;
343  case NeonTypeFlags::Poly8:
344    return Context.SignedCharTy;
345  case NeonTypeFlags::Poly16:
346    return Context.ShortTy;
347  case NeonTypeFlags::Float16:
348    return Context.UnsignedShortTy;
349  case NeonTypeFlags::Float32:
350    return Context.FloatTy;
351  }
352  llvm_unreachable("Invalid NeonTypeFlag!");
353}
354
355bool Sema::CheckARMBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) {
356  llvm::APSInt Result;
357
358  uint64_t mask = 0;
359  unsigned TV = 0;
360  int PtrArgNum = -1;
361  bool HasConstPtr = false;
362  switch (BuiltinID) {
363#define GET_NEON_OVERLOAD_CHECK
364#include "clang/Basic/arm_neon.inc"
365#undef GET_NEON_OVERLOAD_CHECK
366  }
367
368  // For NEON intrinsics which are overloaded on vector element type, validate
369  // the immediate which specifies which variant to emit.
370  unsigned ImmArg = TheCall->getNumArgs()-1;
371  if (mask) {
372    if (SemaBuiltinConstantArg(TheCall, ImmArg, Result))
373      return true;
374
375    TV = Result.getLimitedValue(64);
376    if ((TV > 63) || (mask & (1ULL << TV)) == 0)
377      return Diag(TheCall->getLocStart(), diag::err_invalid_neon_type_code)
378        << TheCall->getArg(ImmArg)->getSourceRange();
379  }
380
381  if (PtrArgNum >= 0) {
382    // Check that pointer arguments have the specified type.
383    Expr *Arg = TheCall->getArg(PtrArgNum);
384    if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Arg))
385      Arg = ICE->getSubExpr();
386    ExprResult RHS = DefaultFunctionArrayLvalueConversion(Arg);
387    QualType RHSTy = RHS.get()->getType();
388    QualType EltTy = getNeonEltType(NeonTypeFlags(TV), Context);
389    if (HasConstPtr)
390      EltTy = EltTy.withConst();
391    QualType LHSTy = Context.getPointerType(EltTy);
392    AssignConvertType ConvTy;
393    ConvTy = CheckSingleAssignmentConstraints(LHSTy, RHS);
394    if (RHS.isInvalid())
395      return true;
396    if (DiagnoseAssignmentResult(ConvTy, Arg->getLocStart(), LHSTy, RHSTy,
397                                 RHS.get(), AA_Assigning))
398      return true;
399  }
400
401  // For NEON intrinsics which take an immediate value as part of the
402  // instruction, range check them here.
403  unsigned i = 0, l = 0, u = 0;
404  switch (BuiltinID) {
405  default: return false;
406  case ARM::BI__builtin_arm_ssat: i = 1; l = 1; u = 31; break;
407  case ARM::BI__builtin_arm_usat: i = 1; u = 31; break;
408  case ARM::BI__builtin_arm_vcvtr_f:
409  case ARM::BI__builtin_arm_vcvtr_d: i = 1; u = 1; break;
410#define GET_NEON_IMMEDIATE_CHECK
411#include "clang/Basic/arm_neon.inc"
412#undef GET_NEON_IMMEDIATE_CHECK
413  };
414
415  // We can't check the value of a dependent argument.
416  if (TheCall->getArg(i)->isTypeDependent() ||
417      TheCall->getArg(i)->isValueDependent())
418    return false;
419
420  // Check that the immediate argument is actually a constant.
421  if (SemaBuiltinConstantArg(TheCall, i, Result))
422    return true;
423
424  // Range check against the upper/lower values for this isntruction.
425  unsigned Val = Result.getZExtValue();
426  if (Val < l || Val > (u + l))
427    return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range)
428      << l << u+l << TheCall->getArg(i)->getSourceRange();
429
430  // FIXME: VFP Intrinsics should error if VFP not present.
431  return false;
432}
433
434bool Sema::CheckMipsBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) {
435  unsigned i = 0, l = 0, u = 0;
436  switch (BuiltinID) {
437  default: return false;
438  case Mips::BI__builtin_mips_wrdsp: i = 1; l = 0; u = 63; break;
439  case Mips::BI__builtin_mips_rddsp: i = 0; l = 0; u = 63; break;
440  case Mips::BI__builtin_mips_append: i = 2; l = 0; u = 31; break;
441  case Mips::BI__builtin_mips_balign: i = 2; l = 0; u = 3; break;
442  case Mips::BI__builtin_mips_precr_sra_ph_w: i = 2; l = 0; u = 31; break;
443  case Mips::BI__builtin_mips_precr_sra_r_ph_w: i = 2; l = 0; u = 31; break;
444  case Mips::BI__builtin_mips_prepend: i = 2; l = 0; u = 31; break;
445  };
446
447  // We can't check the value of a dependent argument.
448  if (TheCall->getArg(i)->isTypeDependent() ||
449      TheCall->getArg(i)->isValueDependent())
450    return false;
451
452  // Check that the immediate argument is actually a constant.
453  llvm::APSInt Result;
454  if (SemaBuiltinConstantArg(TheCall, i, Result))
455    return true;
456
457  // Range check against the upper/lower values for this instruction.
458  unsigned Val = Result.getZExtValue();
459  if (Val < l || Val > u)
460    return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range)
461      << l << u << TheCall->getArg(i)->getSourceRange();
462
463  return false;
464}
465
466/// Given a FunctionDecl's FormatAttr, attempts to populate the FomatStringInfo
467/// parameter with the FormatAttr's correct format_idx and firstDataArg.
468/// Returns true when the format fits the function and the FormatStringInfo has
469/// been populated.
470bool Sema::getFormatStringInfo(const FormatAttr *Format, bool IsCXXMember,
471                               FormatStringInfo *FSI) {
472  FSI->HasVAListArg = Format->getFirstArg() == 0;
473  FSI->FormatIdx = Format->getFormatIdx() - 1;
474  FSI->FirstDataArg = FSI->HasVAListArg ? 0 : Format->getFirstArg() - 1;
475
476  // The way the format attribute works in GCC, the implicit this argument
477  // of member functions is counted. However, it doesn't appear in our own
478  // lists, so decrement format_idx in that case.
479  if (IsCXXMember) {
480    if(FSI->FormatIdx == 0)
481      return false;
482    --FSI->FormatIdx;
483    if (FSI->FirstDataArg != 0)
484      --FSI->FirstDataArg;
485  }
486  return true;
487}
488
489/// Handles the checks for format strings, non-POD arguments to vararg
490/// functions, and NULL arguments passed to non-NULL parameters.
491void Sema::checkCall(NamedDecl *FDecl, Expr **Args,
492                     unsigned NumArgs,
493                     unsigned NumProtoArgs,
494                     bool IsMemberFunction,
495                     SourceLocation Loc,
496                     SourceRange Range,
497                     VariadicCallType CallType) {
498  // FIXME: This mechanism should be abstracted to be less fragile and
499  // more efficient. For example, just map function ids to custom
500  // handlers.
501
502  // Printf and scanf checking.
503  bool HandledFormatString = false;
504  for (specific_attr_iterator<FormatAttr>
505         I = FDecl->specific_attr_begin<FormatAttr>(),
506         E = FDecl->specific_attr_end<FormatAttr>(); I != E ; ++I)
507    if (CheckFormatArguments(*I, Args, NumArgs, IsMemberFunction, CallType,
508                             Loc, Range))
509        HandledFormatString = true;
510
511  // Refuse POD arguments that weren't caught by the format string
512  // checks above.
513  if (!HandledFormatString && CallType != VariadicDoesNotApply)
514    for (unsigned ArgIdx = NumProtoArgs; ArgIdx < NumArgs; ++ArgIdx)
515      variadicArgumentPODCheck(Args[ArgIdx], CallType);
516
517  for (specific_attr_iterator<NonNullAttr>
518         I = FDecl->specific_attr_begin<NonNullAttr>(),
519         E = FDecl->specific_attr_end<NonNullAttr>(); I != E; ++I)
520    CheckNonNullArguments(*I, Args, Loc);
521
522  // Type safety checking.
523  for (specific_attr_iterator<ArgumentWithTypeTagAttr>
524         i = FDecl->specific_attr_begin<ArgumentWithTypeTagAttr>(),
525         e = FDecl->specific_attr_end<ArgumentWithTypeTagAttr>(); i != e; ++i) {
526    CheckArgumentWithTypeTag(*i, Args);
527  }
528}
529
530/// CheckConstructorCall - Check a constructor call for correctness and safety
531/// properties not enforced by the C type system.
532void Sema::CheckConstructorCall(FunctionDecl *FDecl, Expr **Args,
533                                unsigned NumArgs,
534                                const FunctionProtoType *Proto,
535                                SourceLocation Loc) {
536  VariadicCallType CallType =
537    Proto->isVariadic() ? VariadicConstructor : VariadicDoesNotApply;
538  checkCall(FDecl, Args, NumArgs, Proto->getNumArgs(),
539            /*IsMemberFunction=*/true, Loc, SourceRange(), CallType);
540}
541
542/// CheckFunctionCall - Check a direct function call for various correctness
543/// and safety properties not strictly enforced by the C type system.
544bool Sema::CheckFunctionCall(FunctionDecl *FDecl, CallExpr *TheCall,
545                             const FunctionProtoType *Proto) {
546  bool IsMemberFunction = isa<CXXMemberCallExpr>(TheCall);
547  VariadicCallType CallType = getVariadicCallType(FDecl, Proto,
548                                                  TheCall->getCallee());
549  unsigned NumProtoArgs = Proto ? Proto->getNumArgs() : 0;
550  checkCall(FDecl, TheCall->getArgs(), TheCall->getNumArgs(), NumProtoArgs,
551            IsMemberFunction, TheCall->getRParenLoc(),
552            TheCall->getCallee()->getSourceRange(), CallType);
553
554  IdentifierInfo *FnInfo = FDecl->getIdentifier();
555  // None of the checks below are needed for functions that don't have
556  // simple names (e.g., C++ conversion functions).
557  if (!FnInfo)
558    return false;
559
560  unsigned CMId = FDecl->getMemoryFunctionKind();
561  if (CMId == 0)
562    return false;
563
564  // Handle memory setting and copying functions.
565  if (CMId == Builtin::BIstrlcpy || CMId == Builtin::BIstrlcat)
566    CheckStrlcpycatArguments(TheCall, FnInfo);
567  else if (CMId == Builtin::BIstrncat)
568    CheckStrncatArguments(TheCall, FnInfo);
569  else
570    CheckMemaccessArguments(TheCall, CMId, FnInfo);
571
572  return false;
573}
574
575bool Sema::CheckObjCMethodCall(ObjCMethodDecl *Method, SourceLocation lbrac,
576                               Expr **Args, unsigned NumArgs) {
577  VariadicCallType CallType =
578      Method->isVariadic() ? VariadicMethod : VariadicDoesNotApply;
579
580  checkCall(Method, Args, NumArgs, Method->param_size(),
581            /*IsMemberFunction=*/false,
582            lbrac, Method->getSourceRange(), CallType);
583
584  return false;
585}
586
587bool Sema::CheckBlockCall(NamedDecl *NDecl, CallExpr *TheCall,
588                          const FunctionProtoType *Proto) {
589  const VarDecl *V = dyn_cast<VarDecl>(NDecl);
590  if (!V)
591    return false;
592
593  QualType Ty = V->getType();
594  if (!Ty->isBlockPointerType())
595    return false;
596
597  VariadicCallType CallType =
598      Proto && Proto->isVariadic() ? VariadicBlock : VariadicDoesNotApply ;
599  unsigned NumProtoArgs = Proto ? Proto->getNumArgs() : 0;
600
601  checkCall(NDecl, TheCall->getArgs(), TheCall->getNumArgs(),
602            NumProtoArgs, /*IsMemberFunction=*/false,
603            TheCall->getRParenLoc(),
604            TheCall->getCallee()->getSourceRange(), CallType);
605
606  return false;
607}
608
609ExprResult Sema::SemaAtomicOpsOverloaded(ExprResult TheCallResult,
610                                         AtomicExpr::AtomicOp Op) {
611  CallExpr *TheCall = cast<CallExpr>(TheCallResult.get());
612  DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts());
613
614  // All these operations take one of the following forms:
615  enum {
616    // C    __c11_atomic_init(A *, C)
617    Init,
618    // C    __c11_atomic_load(A *, int)
619    Load,
620    // void __atomic_load(A *, CP, int)
621    Copy,
622    // C    __c11_atomic_add(A *, M, int)
623    Arithmetic,
624    // C    __atomic_exchange_n(A *, CP, int)
625    Xchg,
626    // void __atomic_exchange(A *, C *, CP, int)
627    GNUXchg,
628    // bool __c11_atomic_compare_exchange_strong(A *, C *, CP, int, int)
629    C11CmpXchg,
630    // bool __atomic_compare_exchange(A *, C *, CP, bool, int, int)
631    GNUCmpXchg
632  } Form = Init;
633  const unsigned NumArgs[] = { 2, 2, 3, 3, 3, 4, 5, 6 };
634  const unsigned NumVals[] = { 1, 0, 1, 1, 1, 2, 2, 3 };
635  // where:
636  //   C is an appropriate type,
637  //   A is volatile _Atomic(C) for __c11 builtins and is C for GNU builtins,
638  //   CP is C for __c11 builtins and GNU _n builtins and is C * otherwise,
639  //   M is C if C is an integer, and ptrdiff_t if C is a pointer, and
640  //   the int parameters are for orderings.
641
642  assert(AtomicExpr::AO__c11_atomic_init == 0 &&
643         AtomicExpr::AO__c11_atomic_fetch_xor + 1 == AtomicExpr::AO__atomic_load
644         && "need to update code for modified C11 atomics");
645  bool IsC11 = Op >= AtomicExpr::AO__c11_atomic_init &&
646               Op <= AtomicExpr::AO__c11_atomic_fetch_xor;
647  bool IsN = Op == AtomicExpr::AO__atomic_load_n ||
648             Op == AtomicExpr::AO__atomic_store_n ||
649             Op == AtomicExpr::AO__atomic_exchange_n ||
650             Op == AtomicExpr::AO__atomic_compare_exchange_n;
651  bool IsAddSub = false;
652
653  switch (Op) {
654  case AtomicExpr::AO__c11_atomic_init:
655    Form = Init;
656    break;
657
658  case AtomicExpr::AO__c11_atomic_load:
659  case AtomicExpr::AO__atomic_load_n:
660    Form = Load;
661    break;
662
663  case AtomicExpr::AO__c11_atomic_store:
664  case AtomicExpr::AO__atomic_load:
665  case AtomicExpr::AO__atomic_store:
666  case AtomicExpr::AO__atomic_store_n:
667    Form = Copy;
668    break;
669
670  case AtomicExpr::AO__c11_atomic_fetch_add:
671  case AtomicExpr::AO__c11_atomic_fetch_sub:
672  case AtomicExpr::AO__atomic_fetch_add:
673  case AtomicExpr::AO__atomic_fetch_sub:
674  case AtomicExpr::AO__atomic_add_fetch:
675  case AtomicExpr::AO__atomic_sub_fetch:
676    IsAddSub = true;
677    // Fall through.
678  case AtomicExpr::AO__c11_atomic_fetch_and:
679  case AtomicExpr::AO__c11_atomic_fetch_or:
680  case AtomicExpr::AO__c11_atomic_fetch_xor:
681  case AtomicExpr::AO__atomic_fetch_and:
682  case AtomicExpr::AO__atomic_fetch_or:
683  case AtomicExpr::AO__atomic_fetch_xor:
684  case AtomicExpr::AO__atomic_fetch_nand:
685  case AtomicExpr::AO__atomic_and_fetch:
686  case AtomicExpr::AO__atomic_or_fetch:
687  case AtomicExpr::AO__atomic_xor_fetch:
688  case AtomicExpr::AO__atomic_nand_fetch:
689    Form = Arithmetic;
690    break;
691
692  case AtomicExpr::AO__c11_atomic_exchange:
693  case AtomicExpr::AO__atomic_exchange_n:
694    Form = Xchg;
695    break;
696
697  case AtomicExpr::AO__atomic_exchange:
698    Form = GNUXchg;
699    break;
700
701  case AtomicExpr::AO__c11_atomic_compare_exchange_strong:
702  case AtomicExpr::AO__c11_atomic_compare_exchange_weak:
703    Form = C11CmpXchg;
704    break;
705
706  case AtomicExpr::AO__atomic_compare_exchange:
707  case AtomicExpr::AO__atomic_compare_exchange_n:
708    Form = GNUCmpXchg;
709    break;
710  }
711
712  // Check we have the right number of arguments.
713  if (TheCall->getNumArgs() < NumArgs[Form]) {
714    Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args)
715      << 0 << NumArgs[Form] << TheCall->getNumArgs()
716      << TheCall->getCallee()->getSourceRange();
717    return ExprError();
718  } else if (TheCall->getNumArgs() > NumArgs[Form]) {
719    Diag(TheCall->getArg(NumArgs[Form])->getLocStart(),
720         diag::err_typecheck_call_too_many_args)
721      << 0 << NumArgs[Form] << TheCall->getNumArgs()
722      << TheCall->getCallee()->getSourceRange();
723    return ExprError();
724  }
725
726  // Inspect the first argument of the atomic operation.
727  Expr *Ptr = TheCall->getArg(0);
728  Ptr = DefaultFunctionArrayLvalueConversion(Ptr).get();
729  const PointerType *pointerType = Ptr->getType()->getAs<PointerType>();
730  if (!pointerType) {
731    Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer)
732      << Ptr->getType() << Ptr->getSourceRange();
733    return ExprError();
734  }
735
736  // For a __c11 builtin, this should be a pointer to an _Atomic type.
737  QualType AtomTy = pointerType->getPointeeType(); // 'A'
738  QualType ValType = AtomTy; // 'C'
739  if (IsC11) {
740    if (!AtomTy->isAtomicType()) {
741      Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic)
742        << Ptr->getType() << Ptr->getSourceRange();
743      return ExprError();
744    }
745    if (AtomTy.isConstQualified()) {
746      Diag(DRE->getLocStart(), diag::err_atomic_op_needs_non_const_atomic)
747        << Ptr->getType() << Ptr->getSourceRange();
748      return ExprError();
749    }
750    ValType = AtomTy->getAs<AtomicType>()->getValueType();
751  }
752
753  // For an arithmetic operation, the implied arithmetic must be well-formed.
754  if (Form == Arithmetic) {
755    // gcc does not enforce these rules for GNU atomics, but we do so for sanity.
756    if (IsAddSub && !ValType->isIntegerType() && !ValType->isPointerType()) {
757      Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic_int_or_ptr)
758        << IsC11 << Ptr->getType() << Ptr->getSourceRange();
759      return ExprError();
760    }
761    if (!IsAddSub && !ValType->isIntegerType()) {
762      Diag(DRE->getLocStart(), diag::err_atomic_op_bitwise_needs_atomic_int)
763        << IsC11 << Ptr->getType() << Ptr->getSourceRange();
764      return ExprError();
765    }
766  } else if (IsN && !ValType->isIntegerType() && !ValType->isPointerType()) {
767    // For __atomic_*_n operations, the value type must be a scalar integral or
768    // pointer type which is 1, 2, 4, 8 or 16 bytes in length.
769    Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic_int_or_ptr)
770      << IsC11 << Ptr->getType() << Ptr->getSourceRange();
771    return ExprError();
772  }
773
774  if (!IsC11 && !AtomTy.isTriviallyCopyableType(Context)) {
775    // For GNU atomics, require a trivially-copyable type. This is not part of
776    // the GNU atomics specification, but we enforce it for sanity.
777    Diag(DRE->getLocStart(), diag::err_atomic_op_needs_trivial_copy)
778      << Ptr->getType() << Ptr->getSourceRange();
779    return ExprError();
780  }
781
782  // FIXME: For any builtin other than a load, the ValType must not be
783  // const-qualified.
784
785  switch (ValType.getObjCLifetime()) {
786  case Qualifiers::OCL_None:
787  case Qualifiers::OCL_ExplicitNone:
788    // okay
789    break;
790
791  case Qualifiers::OCL_Weak:
792  case Qualifiers::OCL_Strong:
793  case Qualifiers::OCL_Autoreleasing:
794    // FIXME: Can this happen? By this point, ValType should be known
795    // to be trivially copyable.
796    Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership)
797      << ValType << Ptr->getSourceRange();
798    return ExprError();
799  }
800
801  QualType ResultType = ValType;
802  if (Form == Copy || Form == GNUXchg || Form == Init)
803    ResultType = Context.VoidTy;
804  else if (Form == C11CmpXchg || Form == GNUCmpXchg)
805    ResultType = Context.BoolTy;
806
807  // The type of a parameter passed 'by value'. In the GNU atomics, such
808  // arguments are actually passed as pointers.
809  QualType ByValType = ValType; // 'CP'
810  if (!IsC11 && !IsN)
811    ByValType = Ptr->getType();
812
813  // The first argument --- the pointer --- has a fixed type; we
814  // deduce the types of the rest of the arguments accordingly.  Walk
815  // the remaining arguments, converting them to the deduced value type.
816  for (unsigned i = 1; i != NumArgs[Form]; ++i) {
817    QualType Ty;
818    if (i < NumVals[Form] + 1) {
819      switch (i) {
820      case 1:
821        // The second argument is the non-atomic operand. For arithmetic, this
822        // is always passed by value, and for a compare_exchange it is always
823        // passed by address. For the rest, GNU uses by-address and C11 uses
824        // by-value.
825        assert(Form != Load);
826        if (Form == Init || (Form == Arithmetic && ValType->isIntegerType()))
827          Ty = ValType;
828        else if (Form == Copy || Form == Xchg)
829          Ty = ByValType;
830        else if (Form == Arithmetic)
831          Ty = Context.getPointerDiffType();
832        else
833          Ty = Context.getPointerType(ValType.getUnqualifiedType());
834        break;
835      case 2:
836        // The third argument to compare_exchange / GNU exchange is a
837        // (pointer to a) desired value.
838        Ty = ByValType;
839        break;
840      case 3:
841        // The fourth argument to GNU compare_exchange is a 'weak' flag.
842        Ty = Context.BoolTy;
843        break;
844      }
845    } else {
846      // The order(s) are always converted to int.
847      Ty = Context.IntTy;
848    }
849
850    InitializedEntity Entity =
851        InitializedEntity::InitializeParameter(Context, Ty, false);
852    ExprResult Arg = TheCall->getArg(i);
853    Arg = PerformCopyInitialization(Entity, SourceLocation(), Arg);
854    if (Arg.isInvalid())
855      return true;
856    TheCall->setArg(i, Arg.get());
857  }
858
859  // Permute the arguments into a 'consistent' order.
860  SmallVector<Expr*, 5> SubExprs;
861  SubExprs.push_back(Ptr);
862  switch (Form) {
863  case Init:
864    // Note, AtomicExpr::getVal1() has a special case for this atomic.
865    SubExprs.push_back(TheCall->getArg(1)); // Val1
866    break;
867  case Load:
868    SubExprs.push_back(TheCall->getArg(1)); // Order
869    break;
870  case Copy:
871  case Arithmetic:
872  case Xchg:
873    SubExprs.push_back(TheCall->getArg(2)); // Order
874    SubExprs.push_back(TheCall->getArg(1)); // Val1
875    break;
876  case GNUXchg:
877    // Note, AtomicExpr::getVal2() has a special case for this atomic.
878    SubExprs.push_back(TheCall->getArg(3)); // Order
879    SubExprs.push_back(TheCall->getArg(1)); // Val1
880    SubExprs.push_back(TheCall->getArg(2)); // Val2
881    break;
882  case C11CmpXchg:
883    SubExprs.push_back(TheCall->getArg(3)); // Order
884    SubExprs.push_back(TheCall->getArg(1)); // Val1
885    SubExprs.push_back(TheCall->getArg(4)); // OrderFail
886    SubExprs.push_back(TheCall->getArg(2)); // Val2
887    break;
888  case GNUCmpXchg:
889    SubExprs.push_back(TheCall->getArg(4)); // Order
890    SubExprs.push_back(TheCall->getArg(1)); // Val1
891    SubExprs.push_back(TheCall->getArg(5)); // OrderFail
892    SubExprs.push_back(TheCall->getArg(2)); // Val2
893    SubExprs.push_back(TheCall->getArg(3)); // Weak
894    break;
895  }
896
897  return Owned(new (Context) AtomicExpr(TheCall->getCallee()->getLocStart(),
898                                        SubExprs, ResultType, Op,
899                                        TheCall->getRParenLoc()));
900}
901
902
903/// checkBuiltinArgument - Given a call to a builtin function, perform
904/// normal type-checking on the given argument, updating the call in
905/// place.  This is useful when a builtin function requires custom
906/// type-checking for some of its arguments but not necessarily all of
907/// them.
908///
909/// Returns true on error.
910static bool checkBuiltinArgument(Sema &S, CallExpr *E, unsigned ArgIndex) {
911  FunctionDecl *Fn = E->getDirectCallee();
912  assert(Fn && "builtin call without direct callee!");
913
914  ParmVarDecl *Param = Fn->getParamDecl(ArgIndex);
915  InitializedEntity Entity =
916    InitializedEntity::InitializeParameter(S.Context, Param);
917
918  ExprResult Arg = E->getArg(0);
919  Arg = S.PerformCopyInitialization(Entity, SourceLocation(), Arg);
920  if (Arg.isInvalid())
921    return true;
922
923  E->setArg(ArgIndex, Arg.take());
924  return false;
925}
926
927/// SemaBuiltinAtomicOverloaded - We have a call to a function like
928/// __sync_fetch_and_add, which is an overloaded function based on the pointer
929/// type of its first argument.  The main ActOnCallExpr routines have already
930/// promoted the types of arguments because all of these calls are prototyped as
931/// void(...).
932///
933/// This function goes through and does final semantic checking for these
934/// builtins,
935ExprResult
936Sema::SemaBuiltinAtomicOverloaded(ExprResult TheCallResult) {
937  CallExpr *TheCall = (CallExpr *)TheCallResult.get();
938  DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts());
939  FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl());
940
941  // Ensure that we have at least one argument to do type inference from.
942  if (TheCall->getNumArgs() < 1) {
943    Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least)
944      << 0 << 1 << TheCall->getNumArgs()
945      << TheCall->getCallee()->getSourceRange();
946    return ExprError();
947  }
948
949  // Inspect the first argument of the atomic builtin.  This should always be
950  // a pointer type, whose element is an integral scalar or pointer type.
951  // Because it is a pointer type, we don't have to worry about any implicit
952  // casts here.
953  // FIXME: We don't allow floating point scalars as input.
954  Expr *FirstArg = TheCall->getArg(0);
955  ExprResult FirstArgResult = DefaultFunctionArrayLvalueConversion(FirstArg);
956  if (FirstArgResult.isInvalid())
957    return ExprError();
958  FirstArg = FirstArgResult.take();
959  TheCall->setArg(0, FirstArg);
960
961  const PointerType *pointerType = FirstArg->getType()->getAs<PointerType>();
962  if (!pointerType) {
963    Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer)
964      << FirstArg->getType() << FirstArg->getSourceRange();
965    return ExprError();
966  }
967
968  QualType ValType = pointerType->getPointeeType();
969  if (!ValType->isIntegerType() && !ValType->isAnyPointerType() &&
970      !ValType->isBlockPointerType()) {
971    Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer_intptr)
972      << FirstArg->getType() << FirstArg->getSourceRange();
973    return ExprError();
974  }
975
976  switch (ValType.getObjCLifetime()) {
977  case Qualifiers::OCL_None:
978  case Qualifiers::OCL_ExplicitNone:
979    // okay
980    break;
981
982  case Qualifiers::OCL_Weak:
983  case Qualifiers::OCL_Strong:
984  case Qualifiers::OCL_Autoreleasing:
985    Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership)
986      << ValType << FirstArg->getSourceRange();
987    return ExprError();
988  }
989
990  // Strip any qualifiers off ValType.
991  ValType = ValType.getUnqualifiedType();
992
993  // The majority of builtins return a value, but a few have special return
994  // types, so allow them to override appropriately below.
995  QualType ResultType = ValType;
996
997  // We need to figure out which concrete builtin this maps onto.  For example,
998  // __sync_fetch_and_add with a 2 byte object turns into
999  // __sync_fetch_and_add_2.
1000#define BUILTIN_ROW(x) \
1001  { Builtin::BI##x##_1, Builtin::BI##x##_2, Builtin::BI##x##_4, \
1002    Builtin::BI##x##_8, Builtin::BI##x##_16 }
1003
1004  static const unsigned BuiltinIndices[][5] = {
1005    BUILTIN_ROW(__sync_fetch_and_add),
1006    BUILTIN_ROW(__sync_fetch_and_sub),
1007    BUILTIN_ROW(__sync_fetch_and_or),
1008    BUILTIN_ROW(__sync_fetch_and_and),
1009    BUILTIN_ROW(__sync_fetch_and_xor),
1010
1011    BUILTIN_ROW(__sync_add_and_fetch),
1012    BUILTIN_ROW(__sync_sub_and_fetch),
1013    BUILTIN_ROW(__sync_and_and_fetch),
1014    BUILTIN_ROW(__sync_or_and_fetch),
1015    BUILTIN_ROW(__sync_xor_and_fetch),
1016
1017    BUILTIN_ROW(__sync_val_compare_and_swap),
1018    BUILTIN_ROW(__sync_bool_compare_and_swap),
1019    BUILTIN_ROW(__sync_lock_test_and_set),
1020    BUILTIN_ROW(__sync_lock_release),
1021    BUILTIN_ROW(__sync_swap)
1022  };
1023#undef BUILTIN_ROW
1024
1025  // Determine the index of the size.
1026  unsigned SizeIndex;
1027  switch (Context.getTypeSizeInChars(ValType).getQuantity()) {
1028  case 1: SizeIndex = 0; break;
1029  case 2: SizeIndex = 1; break;
1030  case 4: SizeIndex = 2; break;
1031  case 8: SizeIndex = 3; break;
1032  case 16: SizeIndex = 4; break;
1033  default:
1034    Diag(DRE->getLocStart(), diag::err_atomic_builtin_pointer_size)
1035      << FirstArg->getType() << FirstArg->getSourceRange();
1036    return ExprError();
1037  }
1038
1039  // Each of these builtins has one pointer argument, followed by some number of
1040  // values (0, 1 or 2) followed by a potentially empty varags list of stuff
1041  // that we ignore.  Find out which row of BuiltinIndices to read from as well
1042  // as the number of fixed args.
1043  unsigned BuiltinID = FDecl->getBuiltinID();
1044  unsigned BuiltinIndex, NumFixed = 1;
1045  switch (BuiltinID) {
1046  default: llvm_unreachable("Unknown overloaded atomic builtin!");
1047  case Builtin::BI__sync_fetch_and_add:
1048  case Builtin::BI__sync_fetch_and_add_1:
1049  case Builtin::BI__sync_fetch_and_add_2:
1050  case Builtin::BI__sync_fetch_and_add_4:
1051  case Builtin::BI__sync_fetch_and_add_8:
1052  case Builtin::BI__sync_fetch_and_add_16:
1053    BuiltinIndex = 0;
1054    break;
1055
1056  case Builtin::BI__sync_fetch_and_sub:
1057  case Builtin::BI__sync_fetch_and_sub_1:
1058  case Builtin::BI__sync_fetch_and_sub_2:
1059  case Builtin::BI__sync_fetch_and_sub_4:
1060  case Builtin::BI__sync_fetch_and_sub_8:
1061  case Builtin::BI__sync_fetch_and_sub_16:
1062    BuiltinIndex = 1;
1063    break;
1064
1065  case Builtin::BI__sync_fetch_and_or:
1066  case Builtin::BI__sync_fetch_and_or_1:
1067  case Builtin::BI__sync_fetch_and_or_2:
1068  case Builtin::BI__sync_fetch_and_or_4:
1069  case Builtin::BI__sync_fetch_and_or_8:
1070  case Builtin::BI__sync_fetch_and_or_16:
1071    BuiltinIndex = 2;
1072    break;
1073
1074  case Builtin::BI__sync_fetch_and_and:
1075  case Builtin::BI__sync_fetch_and_and_1:
1076  case Builtin::BI__sync_fetch_and_and_2:
1077  case Builtin::BI__sync_fetch_and_and_4:
1078  case Builtin::BI__sync_fetch_and_and_8:
1079  case Builtin::BI__sync_fetch_and_and_16:
1080    BuiltinIndex = 3;
1081    break;
1082
1083  case Builtin::BI__sync_fetch_and_xor:
1084  case Builtin::BI__sync_fetch_and_xor_1:
1085  case Builtin::BI__sync_fetch_and_xor_2:
1086  case Builtin::BI__sync_fetch_and_xor_4:
1087  case Builtin::BI__sync_fetch_and_xor_8:
1088  case Builtin::BI__sync_fetch_and_xor_16:
1089    BuiltinIndex = 4;
1090    break;
1091
1092  case Builtin::BI__sync_add_and_fetch:
1093  case Builtin::BI__sync_add_and_fetch_1:
1094  case Builtin::BI__sync_add_and_fetch_2:
1095  case Builtin::BI__sync_add_and_fetch_4:
1096  case Builtin::BI__sync_add_and_fetch_8:
1097  case Builtin::BI__sync_add_and_fetch_16:
1098    BuiltinIndex = 5;
1099    break;
1100
1101  case Builtin::BI__sync_sub_and_fetch:
1102  case Builtin::BI__sync_sub_and_fetch_1:
1103  case Builtin::BI__sync_sub_and_fetch_2:
1104  case Builtin::BI__sync_sub_and_fetch_4:
1105  case Builtin::BI__sync_sub_and_fetch_8:
1106  case Builtin::BI__sync_sub_and_fetch_16:
1107    BuiltinIndex = 6;
1108    break;
1109
1110  case Builtin::BI__sync_and_and_fetch:
1111  case Builtin::BI__sync_and_and_fetch_1:
1112  case Builtin::BI__sync_and_and_fetch_2:
1113  case Builtin::BI__sync_and_and_fetch_4:
1114  case Builtin::BI__sync_and_and_fetch_8:
1115  case Builtin::BI__sync_and_and_fetch_16:
1116    BuiltinIndex = 7;
1117    break;
1118
1119  case Builtin::BI__sync_or_and_fetch:
1120  case Builtin::BI__sync_or_and_fetch_1:
1121  case Builtin::BI__sync_or_and_fetch_2:
1122  case Builtin::BI__sync_or_and_fetch_4:
1123  case Builtin::BI__sync_or_and_fetch_8:
1124  case Builtin::BI__sync_or_and_fetch_16:
1125    BuiltinIndex = 8;
1126    break;
1127
1128  case Builtin::BI__sync_xor_and_fetch:
1129  case Builtin::BI__sync_xor_and_fetch_1:
1130  case Builtin::BI__sync_xor_and_fetch_2:
1131  case Builtin::BI__sync_xor_and_fetch_4:
1132  case Builtin::BI__sync_xor_and_fetch_8:
1133  case Builtin::BI__sync_xor_and_fetch_16:
1134    BuiltinIndex = 9;
1135    break;
1136
1137  case Builtin::BI__sync_val_compare_and_swap:
1138  case Builtin::BI__sync_val_compare_and_swap_1:
1139  case Builtin::BI__sync_val_compare_and_swap_2:
1140  case Builtin::BI__sync_val_compare_and_swap_4:
1141  case Builtin::BI__sync_val_compare_and_swap_8:
1142  case Builtin::BI__sync_val_compare_and_swap_16:
1143    BuiltinIndex = 10;
1144    NumFixed = 2;
1145    break;
1146
1147  case Builtin::BI__sync_bool_compare_and_swap:
1148  case Builtin::BI__sync_bool_compare_and_swap_1:
1149  case Builtin::BI__sync_bool_compare_and_swap_2:
1150  case Builtin::BI__sync_bool_compare_and_swap_4:
1151  case Builtin::BI__sync_bool_compare_and_swap_8:
1152  case Builtin::BI__sync_bool_compare_and_swap_16:
1153    BuiltinIndex = 11;
1154    NumFixed = 2;
1155    ResultType = Context.BoolTy;
1156    break;
1157
1158  case Builtin::BI__sync_lock_test_and_set:
1159  case Builtin::BI__sync_lock_test_and_set_1:
1160  case Builtin::BI__sync_lock_test_and_set_2:
1161  case Builtin::BI__sync_lock_test_and_set_4:
1162  case Builtin::BI__sync_lock_test_and_set_8:
1163  case Builtin::BI__sync_lock_test_and_set_16:
1164    BuiltinIndex = 12;
1165    break;
1166
1167  case Builtin::BI__sync_lock_release:
1168  case Builtin::BI__sync_lock_release_1:
1169  case Builtin::BI__sync_lock_release_2:
1170  case Builtin::BI__sync_lock_release_4:
1171  case Builtin::BI__sync_lock_release_8:
1172  case Builtin::BI__sync_lock_release_16:
1173    BuiltinIndex = 13;
1174    NumFixed = 0;
1175    ResultType = Context.VoidTy;
1176    break;
1177
1178  case Builtin::BI__sync_swap:
1179  case Builtin::BI__sync_swap_1:
1180  case Builtin::BI__sync_swap_2:
1181  case Builtin::BI__sync_swap_4:
1182  case Builtin::BI__sync_swap_8:
1183  case Builtin::BI__sync_swap_16:
1184    BuiltinIndex = 14;
1185    break;
1186  }
1187
1188  // Now that we know how many fixed arguments we expect, first check that we
1189  // have at least that many.
1190  if (TheCall->getNumArgs() < 1+NumFixed) {
1191    Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least)
1192      << 0 << 1+NumFixed << TheCall->getNumArgs()
1193      << TheCall->getCallee()->getSourceRange();
1194    return ExprError();
1195  }
1196
1197  // Get the decl for the concrete builtin from this, we can tell what the
1198  // concrete integer type we should convert to is.
1199  unsigned NewBuiltinID = BuiltinIndices[BuiltinIndex][SizeIndex];
1200  const char *NewBuiltinName = Context.BuiltinInfo.GetName(NewBuiltinID);
1201  IdentifierInfo *NewBuiltinII = PP.getIdentifierInfo(NewBuiltinName);
1202  FunctionDecl *NewBuiltinDecl =
1203    cast<FunctionDecl>(LazilyCreateBuiltin(NewBuiltinII, NewBuiltinID,
1204                                           TUScope, false, DRE->getLocStart()));
1205
1206  // The first argument --- the pointer --- has a fixed type; we
1207  // deduce the types of the rest of the arguments accordingly.  Walk
1208  // the remaining arguments, converting them to the deduced value type.
1209  for (unsigned i = 0; i != NumFixed; ++i) {
1210    ExprResult Arg = TheCall->getArg(i+1);
1211
1212    // GCC does an implicit conversion to the pointer or integer ValType.  This
1213    // can fail in some cases (1i -> int**), check for this error case now.
1214    // Initialize the argument.
1215    InitializedEntity Entity = InitializedEntity::InitializeParameter(Context,
1216                                                   ValType, /*consume*/ false);
1217    Arg = PerformCopyInitialization(Entity, SourceLocation(), Arg);
1218    if (Arg.isInvalid())
1219      return ExprError();
1220
1221    // Okay, we have something that *can* be converted to the right type.  Check
1222    // to see if there is a potentially weird extension going on here.  This can
1223    // happen when you do an atomic operation on something like an char* and
1224    // pass in 42.  The 42 gets converted to char.  This is even more strange
1225    // for things like 45.123 -> char, etc.
1226    // FIXME: Do this check.
1227    TheCall->setArg(i+1, Arg.take());
1228  }
1229
1230  ASTContext& Context = this->getASTContext();
1231
1232  // Create a new DeclRefExpr to refer to the new decl.
1233  DeclRefExpr* NewDRE = DeclRefExpr::Create(
1234      Context,
1235      DRE->getQualifierLoc(),
1236      SourceLocation(),
1237      NewBuiltinDecl,
1238      /*enclosing*/ false,
1239      DRE->getLocation(),
1240      Context.BuiltinFnTy,
1241      DRE->getValueKind());
1242
1243  // Set the callee in the CallExpr.
1244  // FIXME: This loses syntactic information.
1245  QualType CalleePtrTy = Context.getPointerType(NewBuiltinDecl->getType());
1246  ExprResult PromotedCall = ImpCastExprToType(NewDRE, CalleePtrTy,
1247                                              CK_BuiltinFnToFnPtr);
1248  TheCall->setCallee(PromotedCall.take());
1249
1250  // Change the result type of the call to match the original value type. This
1251  // is arbitrary, but the codegen for these builtins ins design to handle it
1252  // gracefully.
1253  TheCall->setType(ResultType);
1254
1255  return TheCallResult;
1256}
1257
1258/// CheckObjCString - Checks that the argument to the builtin
1259/// CFString constructor is correct
1260/// Note: It might also make sense to do the UTF-16 conversion here (would
1261/// simplify the backend).
1262bool Sema::CheckObjCString(Expr *Arg) {
1263  Arg = Arg->IgnoreParenCasts();
1264  StringLiteral *Literal = dyn_cast<StringLiteral>(Arg);
1265
1266  if (!Literal || !Literal->isAscii()) {
1267    Diag(Arg->getLocStart(), diag::err_cfstring_literal_not_string_constant)
1268      << Arg->getSourceRange();
1269    return true;
1270  }
1271
1272  if (Literal->containsNonAsciiOrNull()) {
1273    StringRef String = Literal->getString();
1274    unsigned NumBytes = String.size();
1275    SmallVector<UTF16, 128> ToBuf(NumBytes);
1276    const UTF8 *FromPtr = (const UTF8 *)String.data();
1277    UTF16 *ToPtr = &ToBuf[0];
1278
1279    ConversionResult Result = ConvertUTF8toUTF16(&FromPtr, FromPtr + NumBytes,
1280                                                 &ToPtr, ToPtr + NumBytes,
1281                                                 strictConversion);
1282    // Check for conversion failure.
1283    if (Result != conversionOK)
1284      Diag(Arg->getLocStart(),
1285           diag::warn_cfstring_truncated) << Arg->getSourceRange();
1286  }
1287  return false;
1288}
1289
1290/// SemaBuiltinVAStart - Check the arguments to __builtin_va_start for validity.
1291/// Emit an error and return true on failure, return false on success.
1292bool Sema::SemaBuiltinVAStart(CallExpr *TheCall) {
1293  Expr *Fn = TheCall->getCallee();
1294  if (TheCall->getNumArgs() > 2) {
1295    Diag(TheCall->getArg(2)->getLocStart(),
1296         diag::err_typecheck_call_too_many_args)
1297      << 0 /*function call*/ << 2 << TheCall->getNumArgs()
1298      << Fn->getSourceRange()
1299      << SourceRange(TheCall->getArg(2)->getLocStart(),
1300                     (*(TheCall->arg_end()-1))->getLocEnd());
1301    return true;
1302  }
1303
1304  if (TheCall->getNumArgs() < 2) {
1305    return Diag(TheCall->getLocEnd(),
1306      diag::err_typecheck_call_too_few_args_at_least)
1307      << 0 /*function call*/ << 2 << TheCall->getNumArgs();
1308  }
1309
1310  // Type-check the first argument normally.
1311  if (checkBuiltinArgument(*this, TheCall, 0))
1312    return true;
1313
1314  // Determine whether the current function is variadic or not.
1315  BlockScopeInfo *CurBlock = getCurBlock();
1316  bool isVariadic;
1317  if (CurBlock)
1318    isVariadic = CurBlock->TheDecl->isVariadic();
1319  else if (FunctionDecl *FD = getCurFunctionDecl())
1320    isVariadic = FD->isVariadic();
1321  else
1322    isVariadic = getCurMethodDecl()->isVariadic();
1323
1324  if (!isVariadic) {
1325    Diag(Fn->getLocStart(), diag::err_va_start_used_in_non_variadic_function);
1326    return true;
1327  }
1328
1329  // Verify that the second argument to the builtin is the last argument of the
1330  // current function or method.
1331  bool SecondArgIsLastNamedArgument = false;
1332  const Expr *Arg = TheCall->getArg(1)->IgnoreParenCasts();
1333
1334  if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(Arg)) {
1335    if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(DR->getDecl())) {
1336      // FIXME: This isn't correct for methods (results in bogus warning).
1337      // Get the last formal in the current function.
1338      const ParmVarDecl *LastArg;
1339      if (CurBlock)
1340        LastArg = *(CurBlock->TheDecl->param_end()-1);
1341      else if (FunctionDecl *FD = getCurFunctionDecl())
1342        LastArg = *(FD->param_end()-1);
1343      else
1344        LastArg = *(getCurMethodDecl()->param_end()-1);
1345      SecondArgIsLastNamedArgument = PV == LastArg;
1346    }
1347  }
1348
1349  if (!SecondArgIsLastNamedArgument)
1350    Diag(TheCall->getArg(1)->getLocStart(),
1351         diag::warn_second_parameter_of_va_start_not_last_named_argument);
1352  return false;
1353}
1354
1355/// SemaBuiltinUnorderedCompare - Handle functions like __builtin_isgreater and
1356/// friends.  This is declared to take (...), so we have to check everything.
1357bool Sema::SemaBuiltinUnorderedCompare(CallExpr *TheCall) {
1358  if (TheCall->getNumArgs() < 2)
1359    return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args)
1360      << 0 << 2 << TheCall->getNumArgs()/*function call*/;
1361  if (TheCall->getNumArgs() > 2)
1362    return Diag(TheCall->getArg(2)->getLocStart(),
1363                diag::err_typecheck_call_too_many_args)
1364      << 0 /*function call*/ << 2 << TheCall->getNumArgs()
1365      << SourceRange(TheCall->getArg(2)->getLocStart(),
1366                     (*(TheCall->arg_end()-1))->getLocEnd());
1367
1368  ExprResult OrigArg0 = TheCall->getArg(0);
1369  ExprResult OrigArg1 = TheCall->getArg(1);
1370
1371  // Do standard promotions between the two arguments, returning their common
1372  // type.
1373  QualType Res = UsualArithmeticConversions(OrigArg0, OrigArg1, false);
1374  if (OrigArg0.isInvalid() || OrigArg1.isInvalid())
1375    return true;
1376
1377  // Make sure any conversions are pushed back into the call; this is
1378  // type safe since unordered compare builtins are declared as "_Bool
1379  // foo(...)".
1380  TheCall->setArg(0, OrigArg0.get());
1381  TheCall->setArg(1, OrigArg1.get());
1382
1383  if (OrigArg0.get()->isTypeDependent() || OrigArg1.get()->isTypeDependent())
1384    return false;
1385
1386  // If the common type isn't a real floating type, then the arguments were
1387  // invalid for this operation.
1388  if (Res.isNull() || !Res->isRealFloatingType())
1389    return Diag(OrigArg0.get()->getLocStart(),
1390                diag::err_typecheck_call_invalid_ordered_compare)
1391      << OrigArg0.get()->getType() << OrigArg1.get()->getType()
1392      << SourceRange(OrigArg0.get()->getLocStart(), OrigArg1.get()->getLocEnd());
1393
1394  return false;
1395}
1396
1397/// SemaBuiltinSemaBuiltinFPClassification - Handle functions like
1398/// __builtin_isnan and friends.  This is declared to take (...), so we have
1399/// to check everything. We expect the last argument to be a floating point
1400/// value.
1401bool Sema::SemaBuiltinFPClassification(CallExpr *TheCall, unsigned NumArgs) {
1402  if (TheCall->getNumArgs() < NumArgs)
1403    return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args)
1404      << 0 << NumArgs << TheCall->getNumArgs()/*function call*/;
1405  if (TheCall->getNumArgs() > NumArgs)
1406    return Diag(TheCall->getArg(NumArgs)->getLocStart(),
1407                diag::err_typecheck_call_too_many_args)
1408      << 0 /*function call*/ << NumArgs << TheCall->getNumArgs()
1409      << SourceRange(TheCall->getArg(NumArgs)->getLocStart(),
1410                     (*(TheCall->arg_end()-1))->getLocEnd());
1411
1412  Expr *OrigArg = TheCall->getArg(NumArgs-1);
1413
1414  if (OrigArg->isTypeDependent())
1415    return false;
1416
1417  // This operation requires a non-_Complex floating-point number.
1418  if (!OrigArg->getType()->isRealFloatingType())
1419    return Diag(OrigArg->getLocStart(),
1420                diag::err_typecheck_call_invalid_unary_fp)
1421      << OrigArg->getType() << OrigArg->getSourceRange();
1422
1423  // If this is an implicit conversion from float -> double, remove it.
1424  if (ImplicitCastExpr *Cast = dyn_cast<ImplicitCastExpr>(OrigArg)) {
1425    Expr *CastArg = Cast->getSubExpr();
1426    if (CastArg->getType()->isSpecificBuiltinType(BuiltinType::Float)) {
1427      assert(Cast->getType()->isSpecificBuiltinType(BuiltinType::Double) &&
1428             "promotion from float to double is the only expected cast here");
1429      Cast->setSubExpr(0);
1430      TheCall->setArg(NumArgs-1, CastArg);
1431    }
1432  }
1433
1434  return false;
1435}
1436
1437/// SemaBuiltinShuffleVector - Handle __builtin_shufflevector.
1438// This is declared to take (...), so we have to check everything.
1439ExprResult Sema::SemaBuiltinShuffleVector(CallExpr *TheCall) {
1440  if (TheCall->getNumArgs() < 2)
1441    return ExprError(Diag(TheCall->getLocEnd(),
1442                          diag::err_typecheck_call_too_few_args_at_least)
1443      << 0 /*function call*/ << 2 << TheCall->getNumArgs()
1444      << TheCall->getSourceRange());
1445
1446  // Determine which of the following types of shufflevector we're checking:
1447  // 1) unary, vector mask: (lhs, mask)
1448  // 2) binary, vector mask: (lhs, rhs, mask)
1449  // 3) binary, scalar mask: (lhs, rhs, index, ..., index)
1450  QualType resType = TheCall->getArg(0)->getType();
1451  unsigned numElements = 0;
1452
1453  if (!TheCall->getArg(0)->isTypeDependent() &&
1454      !TheCall->getArg(1)->isTypeDependent()) {
1455    QualType LHSType = TheCall->getArg(0)->getType();
1456    QualType RHSType = TheCall->getArg(1)->getType();
1457
1458    if (!LHSType->isVectorType() || !RHSType->isVectorType()) {
1459      Diag(TheCall->getLocStart(), diag::err_shufflevector_non_vector)
1460        << SourceRange(TheCall->getArg(0)->getLocStart(),
1461                       TheCall->getArg(1)->getLocEnd());
1462      return ExprError();
1463    }
1464
1465    numElements = LHSType->getAs<VectorType>()->getNumElements();
1466    unsigned numResElements = TheCall->getNumArgs() - 2;
1467
1468    // Check to see if we have a call with 2 vector arguments, the unary shuffle
1469    // with mask.  If so, verify that RHS is an integer vector type with the
1470    // same number of elts as lhs.
1471    if (TheCall->getNumArgs() == 2) {
1472      if (!RHSType->hasIntegerRepresentation() ||
1473          RHSType->getAs<VectorType>()->getNumElements() != numElements)
1474        Diag(TheCall->getLocStart(), diag::err_shufflevector_incompatible_vector)
1475          << SourceRange(TheCall->getArg(1)->getLocStart(),
1476                         TheCall->getArg(1)->getLocEnd());
1477      numResElements = numElements;
1478    }
1479    else if (!Context.hasSameUnqualifiedType(LHSType, RHSType)) {
1480      Diag(TheCall->getLocStart(), diag::err_shufflevector_incompatible_vector)
1481        << SourceRange(TheCall->getArg(0)->getLocStart(),
1482                       TheCall->getArg(1)->getLocEnd());
1483      return ExprError();
1484    } else if (numElements != numResElements) {
1485      QualType eltType = LHSType->getAs<VectorType>()->getElementType();
1486      resType = Context.getVectorType(eltType, numResElements,
1487                                      VectorType::GenericVector);
1488    }
1489  }
1490
1491  for (unsigned i = 2; i < TheCall->getNumArgs(); i++) {
1492    if (TheCall->getArg(i)->isTypeDependent() ||
1493        TheCall->getArg(i)->isValueDependent())
1494      continue;
1495
1496    llvm::APSInt Result(32);
1497    if (!TheCall->getArg(i)->isIntegerConstantExpr(Result, Context))
1498      return ExprError(Diag(TheCall->getLocStart(),
1499                  diag::err_shufflevector_nonconstant_argument)
1500                << TheCall->getArg(i)->getSourceRange());
1501
1502    if (Result.getActiveBits() > 64 || Result.getZExtValue() >= numElements*2)
1503      return ExprError(Diag(TheCall->getLocStart(),
1504                  diag::err_shufflevector_argument_too_large)
1505               << TheCall->getArg(i)->getSourceRange());
1506  }
1507
1508  SmallVector<Expr*, 32> exprs;
1509
1510  for (unsigned i = 0, e = TheCall->getNumArgs(); i != e; i++) {
1511    exprs.push_back(TheCall->getArg(i));
1512    TheCall->setArg(i, 0);
1513  }
1514
1515  return Owned(new (Context) ShuffleVectorExpr(Context, exprs, resType,
1516                                            TheCall->getCallee()->getLocStart(),
1517                                            TheCall->getRParenLoc()));
1518}
1519
1520/// SemaBuiltinPrefetch - Handle __builtin_prefetch.
1521// This is declared to take (const void*, ...) and can take two
1522// optional constant int args.
1523bool Sema::SemaBuiltinPrefetch(CallExpr *TheCall) {
1524  unsigned NumArgs = TheCall->getNumArgs();
1525
1526  if (NumArgs > 3)
1527    return Diag(TheCall->getLocEnd(),
1528             diag::err_typecheck_call_too_many_args_at_most)
1529             << 0 /*function call*/ << 3 << NumArgs
1530             << TheCall->getSourceRange();
1531
1532  // Argument 0 is checked for us and the remaining arguments must be
1533  // constant integers.
1534  for (unsigned i = 1; i != NumArgs; ++i) {
1535    Expr *Arg = TheCall->getArg(i);
1536
1537    // We can't check the value of a dependent argument.
1538    if (Arg->isTypeDependent() || Arg->isValueDependent())
1539      continue;
1540
1541    llvm::APSInt Result;
1542    if (SemaBuiltinConstantArg(TheCall, i, Result))
1543      return true;
1544
1545    // FIXME: gcc issues a warning and rewrites these to 0. These
1546    // seems especially odd for the third argument since the default
1547    // is 3.
1548    if (i == 1) {
1549      if (Result.getLimitedValue() > 1)
1550        return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range)
1551             << "0" << "1" << Arg->getSourceRange();
1552    } else {
1553      if (Result.getLimitedValue() > 3)
1554        return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range)
1555            << "0" << "3" << Arg->getSourceRange();
1556    }
1557  }
1558
1559  return false;
1560}
1561
1562/// SemaBuiltinConstantArg - Handle a check if argument ArgNum of CallExpr
1563/// TheCall is a constant expression.
1564bool Sema::SemaBuiltinConstantArg(CallExpr *TheCall, int ArgNum,
1565                                  llvm::APSInt &Result) {
1566  Expr *Arg = TheCall->getArg(ArgNum);
1567  DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts());
1568  FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl());
1569
1570  if (Arg->isTypeDependent() || Arg->isValueDependent()) return false;
1571
1572  if (!Arg->isIntegerConstantExpr(Result, Context))
1573    return Diag(TheCall->getLocStart(), diag::err_constant_integer_arg_type)
1574                << FDecl->getDeclName() <<  Arg->getSourceRange();
1575
1576  return false;
1577}
1578
1579/// SemaBuiltinObjectSize - Handle __builtin_object_size(void *ptr,
1580/// int type). This simply type checks that type is one of the defined
1581/// constants (0-3).
1582// For compatibility check 0-3, llvm only handles 0 and 2.
1583bool Sema::SemaBuiltinObjectSize(CallExpr *TheCall) {
1584  llvm::APSInt Result;
1585
1586  // We can't check the value of a dependent argument.
1587  if (TheCall->getArg(1)->isTypeDependent() ||
1588      TheCall->getArg(1)->isValueDependent())
1589    return false;
1590
1591  // Check constant-ness first.
1592  if (SemaBuiltinConstantArg(TheCall, 1, Result))
1593    return true;
1594
1595  Expr *Arg = TheCall->getArg(1);
1596  if (Result.getSExtValue() < 0 || Result.getSExtValue() > 3) {
1597    return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range)
1598             << "0" << "3" << SourceRange(Arg->getLocStart(), Arg->getLocEnd());
1599  }
1600
1601  return false;
1602}
1603
1604/// SemaBuiltinLongjmp - Handle __builtin_longjmp(void *env[5], int val).
1605/// This checks that val is a constant 1.
1606bool Sema::SemaBuiltinLongjmp(CallExpr *TheCall) {
1607  Expr *Arg = TheCall->getArg(1);
1608  llvm::APSInt Result;
1609
1610  // TODO: This is less than ideal. Overload this to take a value.
1611  if (SemaBuiltinConstantArg(TheCall, 1, Result))
1612    return true;
1613
1614  if (Result != 1)
1615    return Diag(TheCall->getLocStart(), diag::err_builtin_longjmp_invalid_val)
1616             << SourceRange(Arg->getLocStart(), Arg->getLocEnd());
1617
1618  return false;
1619}
1620
1621// Determine if an expression is a string literal or constant string.
1622// If this function returns false on the arguments to a function expecting a
1623// format string, we will usually need to emit a warning.
1624// True string literals are then checked by CheckFormatString.
1625Sema::StringLiteralCheckType
1626Sema::checkFormatStringExpr(const Expr *E, Expr **Args,
1627                            unsigned NumArgs, bool HasVAListArg,
1628                            unsigned format_idx, unsigned firstDataArg,
1629                            FormatStringType Type, VariadicCallType CallType,
1630                            bool inFunctionCall) {
1631 tryAgain:
1632  if (E->isTypeDependent() || E->isValueDependent())
1633    return SLCT_NotALiteral;
1634
1635  E = E->IgnoreParenCasts();
1636
1637  if (E->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNotNull))
1638    // Technically -Wformat-nonliteral does not warn about this case.
1639    // The behavior of printf and friends in this case is implementation
1640    // dependent.  Ideally if the format string cannot be null then
1641    // it should have a 'nonnull' attribute in the function prototype.
1642    return SLCT_CheckedLiteral;
1643
1644  switch (E->getStmtClass()) {
1645  case Stmt::BinaryConditionalOperatorClass:
1646  case Stmt::ConditionalOperatorClass: {
1647    // The expression is a literal if both sub-expressions were, and it was
1648    // completely checked only if both sub-expressions were checked.
1649    const AbstractConditionalOperator *C =
1650        cast<AbstractConditionalOperator>(E);
1651    StringLiteralCheckType Left =
1652        checkFormatStringExpr(C->getTrueExpr(), Args, NumArgs,
1653                              HasVAListArg, format_idx, firstDataArg,
1654                              Type, CallType, inFunctionCall);
1655    if (Left == SLCT_NotALiteral)
1656      return SLCT_NotALiteral;
1657    StringLiteralCheckType Right =
1658        checkFormatStringExpr(C->getFalseExpr(), Args, NumArgs,
1659                              HasVAListArg, format_idx, firstDataArg,
1660                              Type, CallType, inFunctionCall);
1661    return Left < Right ? Left : Right;
1662  }
1663
1664  case Stmt::ImplicitCastExprClass: {
1665    E = cast<ImplicitCastExpr>(E)->getSubExpr();
1666    goto tryAgain;
1667  }
1668
1669  case Stmt::OpaqueValueExprClass:
1670    if (const Expr *src = cast<OpaqueValueExpr>(E)->getSourceExpr()) {
1671      E = src;
1672      goto tryAgain;
1673    }
1674    return SLCT_NotALiteral;
1675
1676  case Stmt::PredefinedExprClass:
1677    // While __func__, etc., are technically not string literals, they
1678    // cannot contain format specifiers and thus are not a security
1679    // liability.
1680    return SLCT_UncheckedLiteral;
1681
1682  case Stmt::DeclRefExprClass: {
1683    const DeclRefExpr *DR = cast<DeclRefExpr>(E);
1684
1685    // As an exception, do not flag errors for variables binding to
1686    // const string literals.
1687    if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl())) {
1688      bool isConstant = false;
1689      QualType T = DR->getType();
1690
1691      if (const ArrayType *AT = Context.getAsArrayType(T)) {
1692        isConstant = AT->getElementType().isConstant(Context);
1693      } else if (const PointerType *PT = T->getAs<PointerType>()) {
1694        isConstant = T.isConstant(Context) &&
1695                     PT->getPointeeType().isConstant(Context);
1696      } else if (T->isObjCObjectPointerType()) {
1697        // In ObjC, there is usually no "const ObjectPointer" type,
1698        // so don't check if the pointee type is constant.
1699        isConstant = T.isConstant(Context);
1700      }
1701
1702      if (isConstant) {
1703        if (const Expr *Init = VD->getAnyInitializer()) {
1704          // Look through initializers like const char c[] = { "foo" }
1705          if (const InitListExpr *InitList = dyn_cast<InitListExpr>(Init)) {
1706            if (InitList->isStringLiteralInit())
1707              Init = InitList->getInit(0)->IgnoreParenImpCasts();
1708          }
1709          return checkFormatStringExpr(Init, Args, NumArgs,
1710                                       HasVAListArg, format_idx,
1711                                       firstDataArg, Type, CallType,
1712                                       /*inFunctionCall*/false);
1713        }
1714      }
1715
1716      // For vprintf* functions (i.e., HasVAListArg==true), we add a
1717      // special check to see if the format string is a function parameter
1718      // of the function calling the printf function.  If the function
1719      // has an attribute indicating it is a printf-like function, then we
1720      // should suppress warnings concerning non-literals being used in a call
1721      // to a vprintf function.  For example:
1722      //
1723      // void
1724      // logmessage(char const *fmt __attribute__ (format (printf, 1, 2)), ...){
1725      //      va_list ap;
1726      //      va_start(ap, fmt);
1727      //      vprintf(fmt, ap);  // Do NOT emit a warning about "fmt".
1728      //      ...
1729      //
1730      if (HasVAListArg) {
1731        if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(VD)) {
1732          if (const NamedDecl *ND = dyn_cast<NamedDecl>(PV->getDeclContext())) {
1733            int PVIndex = PV->getFunctionScopeIndex() + 1;
1734            for (specific_attr_iterator<FormatAttr>
1735                 i = ND->specific_attr_begin<FormatAttr>(),
1736                 e = ND->specific_attr_end<FormatAttr>(); i != e ; ++i) {
1737              FormatAttr *PVFormat = *i;
1738              // adjust for implicit parameter
1739              if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(ND))
1740                if (MD->isInstance())
1741                  ++PVIndex;
1742              // We also check if the formats are compatible.
1743              // We can't pass a 'scanf' string to a 'printf' function.
1744              if (PVIndex == PVFormat->getFormatIdx() &&
1745                  Type == GetFormatStringType(PVFormat))
1746                return SLCT_UncheckedLiteral;
1747            }
1748          }
1749        }
1750      }
1751    }
1752
1753    return SLCT_NotALiteral;
1754  }
1755
1756  case Stmt::CallExprClass:
1757  case Stmt::CXXMemberCallExprClass: {
1758    const CallExpr *CE = cast<CallExpr>(E);
1759    if (const NamedDecl *ND = dyn_cast_or_null<NamedDecl>(CE->getCalleeDecl())) {
1760      if (const FormatArgAttr *FA = ND->getAttr<FormatArgAttr>()) {
1761        unsigned ArgIndex = FA->getFormatIdx();
1762        if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(ND))
1763          if (MD->isInstance())
1764            --ArgIndex;
1765        const Expr *Arg = CE->getArg(ArgIndex - 1);
1766
1767        return checkFormatStringExpr(Arg, Args, NumArgs,
1768                                     HasVAListArg, format_idx, firstDataArg,
1769                                     Type, CallType, inFunctionCall);
1770      } else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND)) {
1771        unsigned BuiltinID = FD->getBuiltinID();
1772        if (BuiltinID == Builtin::BI__builtin___CFStringMakeConstantString ||
1773            BuiltinID == Builtin::BI__builtin___NSStringMakeConstantString) {
1774          const Expr *Arg = CE->getArg(0);
1775          return checkFormatStringExpr(Arg, Args, NumArgs,
1776                                       HasVAListArg, format_idx,
1777                                       firstDataArg, Type, CallType,
1778                                       inFunctionCall);
1779        }
1780      }
1781    }
1782
1783    return SLCT_NotALiteral;
1784  }
1785  case Stmt::ObjCStringLiteralClass:
1786  case Stmt::StringLiteralClass: {
1787    const StringLiteral *StrE = NULL;
1788
1789    if (const ObjCStringLiteral *ObjCFExpr = dyn_cast<ObjCStringLiteral>(E))
1790      StrE = ObjCFExpr->getString();
1791    else
1792      StrE = cast<StringLiteral>(E);
1793
1794    if (StrE) {
1795      CheckFormatString(StrE, E, Args, NumArgs, HasVAListArg, format_idx,
1796                        firstDataArg, Type, inFunctionCall, CallType);
1797      return SLCT_CheckedLiteral;
1798    }
1799
1800    return SLCT_NotALiteral;
1801  }
1802
1803  default:
1804    return SLCT_NotALiteral;
1805  }
1806}
1807
1808void
1809Sema::CheckNonNullArguments(const NonNullAttr *NonNull,
1810                            const Expr * const *ExprArgs,
1811                            SourceLocation CallSiteLoc) {
1812  for (NonNullAttr::args_iterator i = NonNull->args_begin(),
1813                                  e = NonNull->args_end();
1814       i != e; ++i) {
1815    const Expr *ArgExpr = ExprArgs[*i];
1816    if (ArgExpr->isNullPointerConstant(Context,
1817                                       Expr::NPC_ValueDependentIsNotNull))
1818      Diag(CallSiteLoc, diag::warn_null_arg) << ArgExpr->getSourceRange();
1819  }
1820}
1821
1822Sema::FormatStringType Sema::GetFormatStringType(const FormatAttr *Format) {
1823  return llvm::StringSwitch<FormatStringType>(Format->getType())
1824  .Case("scanf", FST_Scanf)
1825  .Cases("printf", "printf0", FST_Printf)
1826  .Cases("NSString", "CFString", FST_NSString)
1827  .Case("strftime", FST_Strftime)
1828  .Case("strfmon", FST_Strfmon)
1829  .Cases("kprintf", "cmn_err", "vcmn_err", "zcmn_err", FST_Kprintf)
1830  .Default(FST_Unknown);
1831}
1832
1833/// CheckFormatArguments - Check calls to printf and scanf (and similar
1834/// functions) for correct use of format strings.
1835/// Returns true if a format string has been fully checked.
1836bool Sema::CheckFormatArguments(const FormatAttr *Format, Expr **Args,
1837                                unsigned NumArgs, bool IsCXXMember,
1838                                VariadicCallType CallType,
1839                                SourceLocation Loc, SourceRange Range) {
1840  FormatStringInfo FSI;
1841  if (getFormatStringInfo(Format, IsCXXMember, &FSI))
1842    return CheckFormatArguments(Args, NumArgs, FSI.HasVAListArg, FSI.FormatIdx,
1843                                FSI.FirstDataArg, GetFormatStringType(Format),
1844                                CallType, Loc, Range);
1845  return false;
1846}
1847
1848bool Sema::CheckFormatArguments(Expr **Args, unsigned NumArgs,
1849                                bool HasVAListArg, unsigned format_idx,
1850                                unsigned firstDataArg, FormatStringType Type,
1851                                VariadicCallType CallType,
1852                                SourceLocation Loc, SourceRange Range) {
1853  // CHECK: printf/scanf-like function is called with no format string.
1854  if (format_idx >= NumArgs) {
1855    Diag(Loc, diag::warn_missing_format_string) << Range;
1856    return false;
1857  }
1858
1859  const Expr *OrigFormatExpr = Args[format_idx]->IgnoreParenCasts();
1860
1861  // CHECK: format string is not a string literal.
1862  //
1863  // Dynamically generated format strings are difficult to
1864  // automatically vet at compile time.  Requiring that format strings
1865  // are string literals: (1) permits the checking of format strings by
1866  // the compiler and thereby (2) can practically remove the source of
1867  // many format string exploits.
1868
1869  // Format string can be either ObjC string (e.g. @"%d") or
1870  // C string (e.g. "%d")
1871  // ObjC string uses the same format specifiers as C string, so we can use
1872  // the same format string checking logic for both ObjC and C strings.
1873  StringLiteralCheckType CT =
1874      checkFormatStringExpr(OrigFormatExpr, Args, NumArgs, HasVAListArg,
1875                            format_idx, firstDataArg, Type, CallType);
1876  if (CT != SLCT_NotALiteral)
1877    // Literal format string found, check done!
1878    return CT == SLCT_CheckedLiteral;
1879
1880  // Strftime is particular as it always uses a single 'time' argument,
1881  // so it is safe to pass a non-literal string.
1882  if (Type == FST_Strftime)
1883    return false;
1884
1885  // Do not emit diag when the string param is a macro expansion and the
1886  // format is either NSString or CFString. This is a hack to prevent
1887  // diag when using the NSLocalizedString and CFCopyLocalizedString macros
1888  // which are usually used in place of NS and CF string literals.
1889  if (Type == FST_NSString &&
1890      SourceMgr.isInSystemMacro(Args[format_idx]->getLocStart()))
1891    return false;
1892
1893  // If there are no arguments specified, warn with -Wformat-security, otherwise
1894  // warn only with -Wformat-nonliteral.
1895  if (NumArgs == format_idx+1)
1896    Diag(Args[format_idx]->getLocStart(),
1897         diag::warn_format_nonliteral_noargs)
1898      << OrigFormatExpr->getSourceRange();
1899  else
1900    Diag(Args[format_idx]->getLocStart(),
1901         diag::warn_format_nonliteral)
1902           << OrigFormatExpr->getSourceRange();
1903  return false;
1904}
1905
1906namespace {
1907class CheckFormatHandler : public analyze_format_string::FormatStringHandler {
1908protected:
1909  Sema &S;
1910  const StringLiteral *FExpr;
1911  const Expr *OrigFormatExpr;
1912  const unsigned FirstDataArg;
1913  const unsigned NumDataArgs;
1914  const char *Beg; // Start of format string.
1915  const bool HasVAListArg;
1916  const Expr * const *Args;
1917  const unsigned NumArgs;
1918  unsigned FormatIdx;
1919  llvm::BitVector CoveredArgs;
1920  bool usesPositionalArgs;
1921  bool atFirstArg;
1922  bool inFunctionCall;
1923  Sema::VariadicCallType CallType;
1924public:
1925  CheckFormatHandler(Sema &s, const StringLiteral *fexpr,
1926                     const Expr *origFormatExpr, unsigned firstDataArg,
1927                     unsigned numDataArgs, const char *beg, bool hasVAListArg,
1928                     Expr **args, unsigned numArgs,
1929                     unsigned formatIdx, bool inFunctionCall,
1930                     Sema::VariadicCallType callType)
1931    : S(s), FExpr(fexpr), OrigFormatExpr(origFormatExpr),
1932      FirstDataArg(firstDataArg), NumDataArgs(numDataArgs),
1933      Beg(beg), HasVAListArg(hasVAListArg),
1934      Args(args), NumArgs(numArgs), FormatIdx(formatIdx),
1935      usesPositionalArgs(false), atFirstArg(true),
1936      inFunctionCall(inFunctionCall), CallType(callType) {
1937        CoveredArgs.resize(numDataArgs);
1938        CoveredArgs.reset();
1939      }
1940
1941  void DoneProcessing();
1942
1943  void HandleIncompleteSpecifier(const char *startSpecifier,
1944                                 unsigned specifierLen);
1945
1946  void HandleInvalidLengthModifier(
1947      const analyze_format_string::FormatSpecifier &FS,
1948      const analyze_format_string::ConversionSpecifier &CS,
1949      const char *startSpecifier, unsigned specifierLen, unsigned DiagID);
1950
1951  void HandleNonStandardLengthModifier(
1952      const analyze_format_string::FormatSpecifier &FS,
1953      const char *startSpecifier, unsigned specifierLen);
1954
1955  void HandleNonStandardConversionSpecifier(
1956      const analyze_format_string::ConversionSpecifier &CS,
1957      const char *startSpecifier, unsigned specifierLen);
1958
1959  virtual void HandlePosition(const char *startPos, unsigned posLen);
1960
1961  virtual void HandleInvalidPosition(const char *startSpecifier,
1962                                     unsigned specifierLen,
1963                                     analyze_format_string::PositionContext p);
1964
1965  virtual void HandleZeroPosition(const char *startPos, unsigned posLen);
1966
1967  void HandleNullChar(const char *nullCharacter);
1968
1969  template <typename Range>
1970  static void EmitFormatDiagnostic(Sema &S, bool inFunctionCall,
1971                                   const Expr *ArgumentExpr,
1972                                   PartialDiagnostic PDiag,
1973                                   SourceLocation StringLoc,
1974                                   bool IsStringLocation, Range StringRange,
1975                            ArrayRef<FixItHint> Fixit = ArrayRef<FixItHint>());
1976
1977protected:
1978  bool HandleInvalidConversionSpecifier(unsigned argIndex, SourceLocation Loc,
1979                                        const char *startSpec,
1980                                        unsigned specifierLen,
1981                                        const char *csStart, unsigned csLen);
1982
1983  void HandlePositionalNonpositionalArgs(SourceLocation Loc,
1984                                         const char *startSpec,
1985                                         unsigned specifierLen);
1986
1987  SourceRange getFormatStringRange();
1988  CharSourceRange getSpecifierRange(const char *startSpecifier,
1989                                    unsigned specifierLen);
1990  SourceLocation getLocationOfByte(const char *x);
1991
1992  const Expr *getDataArg(unsigned i) const;
1993
1994  bool CheckNumArgs(const analyze_format_string::FormatSpecifier &FS,
1995                    const analyze_format_string::ConversionSpecifier &CS,
1996                    const char *startSpecifier, unsigned specifierLen,
1997                    unsigned argIndex);
1998
1999  template <typename Range>
2000  void EmitFormatDiagnostic(PartialDiagnostic PDiag, SourceLocation StringLoc,
2001                            bool IsStringLocation, Range StringRange,
2002                            ArrayRef<FixItHint> Fixit = ArrayRef<FixItHint>());
2003
2004  void CheckPositionalAndNonpositionalArgs(
2005      const analyze_format_string::FormatSpecifier *FS);
2006};
2007}
2008
2009SourceRange CheckFormatHandler::getFormatStringRange() {
2010  return OrigFormatExpr->getSourceRange();
2011}
2012
2013CharSourceRange CheckFormatHandler::
2014getSpecifierRange(const char *startSpecifier, unsigned specifierLen) {
2015  SourceLocation Start = getLocationOfByte(startSpecifier);
2016  SourceLocation End   = getLocationOfByte(startSpecifier + specifierLen - 1);
2017
2018  // Advance the end SourceLocation by one due to half-open ranges.
2019  End = End.getLocWithOffset(1);
2020
2021  return CharSourceRange::getCharRange(Start, End);
2022}
2023
2024SourceLocation CheckFormatHandler::getLocationOfByte(const char *x) {
2025  return S.getLocationOfStringLiteralByte(FExpr, x - Beg);
2026}
2027
2028void CheckFormatHandler::HandleIncompleteSpecifier(const char *startSpecifier,
2029                                                   unsigned specifierLen){
2030  EmitFormatDiagnostic(S.PDiag(diag::warn_printf_incomplete_specifier),
2031                       getLocationOfByte(startSpecifier),
2032                       /*IsStringLocation*/true,
2033                       getSpecifierRange(startSpecifier, specifierLen));
2034}
2035
2036void CheckFormatHandler::HandleInvalidLengthModifier(
2037    const analyze_format_string::FormatSpecifier &FS,
2038    const analyze_format_string::ConversionSpecifier &CS,
2039    const char *startSpecifier, unsigned specifierLen, unsigned DiagID) {
2040  using namespace analyze_format_string;
2041
2042  const LengthModifier &LM = FS.getLengthModifier();
2043  CharSourceRange LMRange = getSpecifierRange(LM.getStart(), LM.getLength());
2044
2045  // See if we know how to fix this length modifier.
2046  llvm::Optional<LengthModifier> FixedLM = FS.getCorrectedLengthModifier();
2047  if (FixedLM) {
2048    EmitFormatDiagnostic(S.PDiag(DiagID) << LM.toString() << CS.toString(),
2049                         getLocationOfByte(LM.getStart()),
2050                         /*IsStringLocation*/true,
2051                         getSpecifierRange(startSpecifier, specifierLen));
2052
2053    S.Diag(getLocationOfByte(LM.getStart()), diag::note_format_fix_specifier)
2054      << FixedLM->toString()
2055      << FixItHint::CreateReplacement(LMRange, FixedLM->toString());
2056
2057  } else {
2058    FixItHint Hint;
2059    if (DiagID == diag::warn_format_nonsensical_length)
2060      Hint = FixItHint::CreateRemoval(LMRange);
2061
2062    EmitFormatDiagnostic(S.PDiag(DiagID) << LM.toString() << CS.toString(),
2063                         getLocationOfByte(LM.getStart()),
2064                         /*IsStringLocation*/true,
2065                         getSpecifierRange(startSpecifier, specifierLen),
2066                         Hint);
2067  }
2068}
2069
2070void CheckFormatHandler::HandleNonStandardLengthModifier(
2071    const analyze_format_string::FormatSpecifier &FS,
2072    const char *startSpecifier, unsigned specifierLen) {
2073  using namespace analyze_format_string;
2074
2075  const LengthModifier &LM = FS.getLengthModifier();
2076  CharSourceRange LMRange = getSpecifierRange(LM.getStart(), LM.getLength());
2077
2078  // See if we know how to fix this length modifier.
2079  llvm::Optional<LengthModifier> FixedLM = FS.getCorrectedLengthModifier();
2080  if (FixedLM) {
2081    EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard)
2082                           << LM.toString() << 0,
2083                         getLocationOfByte(LM.getStart()),
2084                         /*IsStringLocation*/true,
2085                         getSpecifierRange(startSpecifier, specifierLen));
2086
2087    S.Diag(getLocationOfByte(LM.getStart()), diag::note_format_fix_specifier)
2088      << FixedLM->toString()
2089      << FixItHint::CreateReplacement(LMRange, FixedLM->toString());
2090
2091  } else {
2092    EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard)
2093                           << LM.toString() << 0,
2094                         getLocationOfByte(LM.getStart()),
2095                         /*IsStringLocation*/true,
2096                         getSpecifierRange(startSpecifier, specifierLen));
2097  }
2098}
2099
2100void CheckFormatHandler::HandleNonStandardConversionSpecifier(
2101    const analyze_format_string::ConversionSpecifier &CS,
2102    const char *startSpecifier, unsigned specifierLen) {
2103  using namespace analyze_format_string;
2104
2105  // See if we know how to fix this conversion specifier.
2106  llvm::Optional<ConversionSpecifier> FixedCS = CS.getStandardSpecifier();
2107  if (FixedCS) {
2108    EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard)
2109                          << CS.toString() << /*conversion specifier*/1,
2110                         getLocationOfByte(CS.getStart()),
2111                         /*IsStringLocation*/true,
2112                         getSpecifierRange(startSpecifier, specifierLen));
2113
2114    CharSourceRange CSRange = getSpecifierRange(CS.getStart(), CS.getLength());
2115    S.Diag(getLocationOfByte(CS.getStart()), diag::note_format_fix_specifier)
2116      << FixedCS->toString()
2117      << FixItHint::CreateReplacement(CSRange, FixedCS->toString());
2118  } else {
2119    EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard)
2120                          << CS.toString() << /*conversion specifier*/1,
2121                         getLocationOfByte(CS.getStart()),
2122                         /*IsStringLocation*/true,
2123                         getSpecifierRange(startSpecifier, specifierLen));
2124  }
2125}
2126
2127void CheckFormatHandler::HandlePosition(const char *startPos,
2128                                        unsigned posLen) {
2129  EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard_positional_arg),
2130                               getLocationOfByte(startPos),
2131                               /*IsStringLocation*/true,
2132                               getSpecifierRange(startPos, posLen));
2133}
2134
2135void
2136CheckFormatHandler::HandleInvalidPosition(const char *startPos, unsigned posLen,
2137                                     analyze_format_string::PositionContext p) {
2138  EmitFormatDiagnostic(S.PDiag(diag::warn_format_invalid_positional_specifier)
2139                         << (unsigned) p,
2140                       getLocationOfByte(startPos), /*IsStringLocation*/true,
2141                       getSpecifierRange(startPos, posLen));
2142}
2143
2144void CheckFormatHandler::HandleZeroPosition(const char *startPos,
2145                                            unsigned posLen) {
2146  EmitFormatDiagnostic(S.PDiag(diag::warn_format_zero_positional_specifier),
2147                               getLocationOfByte(startPos),
2148                               /*IsStringLocation*/true,
2149                               getSpecifierRange(startPos, posLen));
2150}
2151
2152void CheckFormatHandler::HandleNullChar(const char *nullCharacter) {
2153  if (!isa<ObjCStringLiteral>(OrigFormatExpr)) {
2154    // The presence of a null character is likely an error.
2155    EmitFormatDiagnostic(
2156      S.PDiag(diag::warn_printf_format_string_contains_null_char),
2157      getLocationOfByte(nullCharacter), /*IsStringLocation*/true,
2158      getFormatStringRange());
2159  }
2160}
2161
2162// Note that this may return NULL if there was an error parsing or building
2163// one of the argument expressions.
2164const Expr *CheckFormatHandler::getDataArg(unsigned i) const {
2165  return Args[FirstDataArg + i];
2166}
2167
2168void CheckFormatHandler::DoneProcessing() {
2169    // Does the number of data arguments exceed the number of
2170    // format conversions in the format string?
2171  if (!HasVAListArg) {
2172      // Find any arguments that weren't covered.
2173    CoveredArgs.flip();
2174    signed notCoveredArg = CoveredArgs.find_first();
2175    if (notCoveredArg >= 0) {
2176      assert((unsigned)notCoveredArg < NumDataArgs);
2177      if (const Expr *E = getDataArg((unsigned) notCoveredArg)) {
2178        SourceLocation Loc = E->getLocStart();
2179        if (!S.getSourceManager().isInSystemMacro(Loc)) {
2180          EmitFormatDiagnostic(S.PDiag(diag::warn_printf_data_arg_not_used),
2181                               Loc, /*IsStringLocation*/false,
2182                               getFormatStringRange());
2183        }
2184      }
2185    }
2186  }
2187}
2188
2189bool
2190CheckFormatHandler::HandleInvalidConversionSpecifier(unsigned argIndex,
2191                                                     SourceLocation Loc,
2192                                                     const char *startSpec,
2193                                                     unsigned specifierLen,
2194                                                     const char *csStart,
2195                                                     unsigned csLen) {
2196
2197  bool keepGoing = true;
2198  if (argIndex < NumDataArgs) {
2199    // Consider the argument coverered, even though the specifier doesn't
2200    // make sense.
2201    CoveredArgs.set(argIndex);
2202  }
2203  else {
2204    // If argIndex exceeds the number of data arguments we
2205    // don't issue a warning because that is just a cascade of warnings (and
2206    // they may have intended '%%' anyway). We don't want to continue processing
2207    // the format string after this point, however, as we will like just get
2208    // gibberish when trying to match arguments.
2209    keepGoing = false;
2210  }
2211
2212  EmitFormatDiagnostic(S.PDiag(diag::warn_format_invalid_conversion)
2213                         << StringRef(csStart, csLen),
2214                       Loc, /*IsStringLocation*/true,
2215                       getSpecifierRange(startSpec, specifierLen));
2216
2217  return keepGoing;
2218}
2219
2220void
2221CheckFormatHandler::HandlePositionalNonpositionalArgs(SourceLocation Loc,
2222                                                      const char *startSpec,
2223                                                      unsigned specifierLen) {
2224  EmitFormatDiagnostic(
2225    S.PDiag(diag::warn_format_mix_positional_nonpositional_args),
2226    Loc, /*isStringLoc*/true, getSpecifierRange(startSpec, specifierLen));
2227}
2228
2229bool
2230CheckFormatHandler::CheckNumArgs(
2231  const analyze_format_string::FormatSpecifier &FS,
2232  const analyze_format_string::ConversionSpecifier &CS,
2233  const char *startSpecifier, unsigned specifierLen, unsigned argIndex) {
2234
2235  if (argIndex >= NumDataArgs) {
2236    PartialDiagnostic PDiag = FS.usesPositionalArg()
2237      ? (S.PDiag(diag::warn_printf_positional_arg_exceeds_data_args)
2238           << (argIndex+1) << NumDataArgs)
2239      : S.PDiag(diag::warn_printf_insufficient_data_args);
2240    EmitFormatDiagnostic(
2241      PDiag, getLocationOfByte(CS.getStart()), /*IsStringLocation*/true,
2242      getSpecifierRange(startSpecifier, specifierLen));
2243    return false;
2244  }
2245  return true;
2246}
2247
2248template<typename Range>
2249void CheckFormatHandler::EmitFormatDiagnostic(PartialDiagnostic PDiag,
2250                                              SourceLocation Loc,
2251                                              bool IsStringLocation,
2252                                              Range StringRange,
2253                                              ArrayRef<FixItHint> FixIt) {
2254  EmitFormatDiagnostic(S, inFunctionCall, Args[FormatIdx], PDiag,
2255                       Loc, IsStringLocation, StringRange, FixIt);
2256}
2257
2258/// \brief If the format string is not within the funcion call, emit a note
2259/// so that the function call and string are in diagnostic messages.
2260///
2261/// \param InFunctionCall if true, the format string is within the function
2262/// call and only one diagnostic message will be produced.  Otherwise, an
2263/// extra note will be emitted pointing to location of the format string.
2264///
2265/// \param ArgumentExpr the expression that is passed as the format string
2266/// argument in the function call.  Used for getting locations when two
2267/// diagnostics are emitted.
2268///
2269/// \param PDiag the callee should already have provided any strings for the
2270/// diagnostic message.  This function only adds locations and fixits
2271/// to diagnostics.
2272///
2273/// \param Loc primary location for diagnostic.  If two diagnostics are
2274/// required, one will be at Loc and a new SourceLocation will be created for
2275/// the other one.
2276///
2277/// \param IsStringLocation if true, Loc points to the format string should be
2278/// used for the note.  Otherwise, Loc points to the argument list and will
2279/// be used with PDiag.
2280///
2281/// \param StringRange some or all of the string to highlight.  This is
2282/// templated so it can accept either a CharSourceRange or a SourceRange.
2283///
2284/// \param FixIt optional fix it hint for the format string.
2285template<typename Range>
2286void CheckFormatHandler::EmitFormatDiagnostic(Sema &S, bool InFunctionCall,
2287                                              const Expr *ArgumentExpr,
2288                                              PartialDiagnostic PDiag,
2289                                              SourceLocation Loc,
2290                                              bool IsStringLocation,
2291                                              Range StringRange,
2292                                              ArrayRef<FixItHint> FixIt) {
2293  if (InFunctionCall) {
2294    const Sema::SemaDiagnosticBuilder &D = S.Diag(Loc, PDiag);
2295    D << StringRange;
2296    for (ArrayRef<FixItHint>::iterator I = FixIt.begin(), E = FixIt.end();
2297         I != E; ++I) {
2298      D << *I;
2299    }
2300  } else {
2301    S.Diag(IsStringLocation ? ArgumentExpr->getExprLoc() : Loc, PDiag)
2302      << ArgumentExpr->getSourceRange();
2303
2304    const Sema::SemaDiagnosticBuilder &Note =
2305      S.Diag(IsStringLocation ? Loc : StringRange.getBegin(),
2306             diag::note_format_string_defined);
2307
2308    Note << StringRange;
2309    for (ArrayRef<FixItHint>::iterator I = FixIt.begin(), E = FixIt.end();
2310         I != E; ++I) {
2311      Note << *I;
2312    }
2313  }
2314}
2315
2316//===--- CHECK: Printf format string checking ------------------------------===//
2317
2318namespace {
2319class CheckPrintfHandler : public CheckFormatHandler {
2320  bool ObjCContext;
2321public:
2322  CheckPrintfHandler(Sema &s, const StringLiteral *fexpr,
2323                     const Expr *origFormatExpr, unsigned firstDataArg,
2324                     unsigned numDataArgs, bool isObjC,
2325                     const char *beg, bool hasVAListArg,
2326                     Expr **Args, unsigned NumArgs,
2327                     unsigned formatIdx, bool inFunctionCall,
2328                     Sema::VariadicCallType CallType)
2329  : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg,
2330                       numDataArgs, beg, hasVAListArg, Args, NumArgs,
2331                       formatIdx, inFunctionCall, CallType), ObjCContext(isObjC)
2332  {}
2333
2334
2335  bool HandleInvalidPrintfConversionSpecifier(
2336                                      const analyze_printf::PrintfSpecifier &FS,
2337                                      const char *startSpecifier,
2338                                      unsigned specifierLen);
2339
2340  bool HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier &FS,
2341                             const char *startSpecifier,
2342                             unsigned specifierLen);
2343  bool checkFormatExpr(const analyze_printf::PrintfSpecifier &FS,
2344                       const char *StartSpecifier,
2345                       unsigned SpecifierLen,
2346                       const Expr *E);
2347
2348  bool HandleAmount(const analyze_format_string::OptionalAmount &Amt, unsigned k,
2349                    const char *startSpecifier, unsigned specifierLen);
2350  void HandleInvalidAmount(const analyze_printf::PrintfSpecifier &FS,
2351                           const analyze_printf::OptionalAmount &Amt,
2352                           unsigned type,
2353                           const char *startSpecifier, unsigned specifierLen);
2354  void HandleFlag(const analyze_printf::PrintfSpecifier &FS,
2355                  const analyze_printf::OptionalFlag &flag,
2356                  const char *startSpecifier, unsigned specifierLen);
2357  void HandleIgnoredFlag(const analyze_printf::PrintfSpecifier &FS,
2358                         const analyze_printf::OptionalFlag &ignoredFlag,
2359                         const analyze_printf::OptionalFlag &flag,
2360                         const char *startSpecifier, unsigned specifierLen);
2361  bool checkForCStrMembers(const analyze_printf::ArgType &AT,
2362                           const Expr *E, const CharSourceRange &CSR);
2363
2364};
2365}
2366
2367bool CheckPrintfHandler::HandleInvalidPrintfConversionSpecifier(
2368                                      const analyze_printf::PrintfSpecifier &FS,
2369                                      const char *startSpecifier,
2370                                      unsigned specifierLen) {
2371  const analyze_printf::PrintfConversionSpecifier &CS =
2372    FS.getConversionSpecifier();
2373
2374  return HandleInvalidConversionSpecifier(FS.getArgIndex(),
2375                                          getLocationOfByte(CS.getStart()),
2376                                          startSpecifier, specifierLen,
2377                                          CS.getStart(), CS.getLength());
2378}
2379
2380bool CheckPrintfHandler::HandleAmount(
2381                               const analyze_format_string::OptionalAmount &Amt,
2382                               unsigned k, const char *startSpecifier,
2383                               unsigned specifierLen) {
2384
2385  if (Amt.hasDataArgument()) {
2386    if (!HasVAListArg) {
2387      unsigned argIndex = Amt.getArgIndex();
2388      if (argIndex >= NumDataArgs) {
2389        EmitFormatDiagnostic(S.PDiag(diag::warn_printf_asterisk_missing_arg)
2390                               << k,
2391                             getLocationOfByte(Amt.getStart()),
2392                             /*IsStringLocation*/true,
2393                             getSpecifierRange(startSpecifier, specifierLen));
2394        // Don't do any more checking.  We will just emit
2395        // spurious errors.
2396        return false;
2397      }
2398
2399      // Type check the data argument.  It should be an 'int'.
2400      // Although not in conformance with C99, we also allow the argument to be
2401      // an 'unsigned int' as that is a reasonably safe case.  GCC also
2402      // doesn't emit a warning for that case.
2403      CoveredArgs.set(argIndex);
2404      const Expr *Arg = getDataArg(argIndex);
2405      if (!Arg)
2406        return false;
2407
2408      QualType T = Arg->getType();
2409
2410      const analyze_printf::ArgType &AT = Amt.getArgType(S.Context);
2411      assert(AT.isValid());
2412
2413      if (!AT.matchesType(S.Context, T)) {
2414        EmitFormatDiagnostic(S.PDiag(diag::warn_printf_asterisk_wrong_type)
2415                               << k << AT.getRepresentativeTypeName(S.Context)
2416                               << T << Arg->getSourceRange(),
2417                             getLocationOfByte(Amt.getStart()),
2418                             /*IsStringLocation*/true,
2419                             getSpecifierRange(startSpecifier, specifierLen));
2420        // Don't do any more checking.  We will just emit
2421        // spurious errors.
2422        return false;
2423      }
2424    }
2425  }
2426  return true;
2427}
2428
2429void CheckPrintfHandler::HandleInvalidAmount(
2430                                      const analyze_printf::PrintfSpecifier &FS,
2431                                      const analyze_printf::OptionalAmount &Amt,
2432                                      unsigned type,
2433                                      const char *startSpecifier,
2434                                      unsigned specifierLen) {
2435  const analyze_printf::PrintfConversionSpecifier &CS =
2436    FS.getConversionSpecifier();
2437
2438  FixItHint fixit =
2439    Amt.getHowSpecified() == analyze_printf::OptionalAmount::Constant
2440      ? FixItHint::CreateRemoval(getSpecifierRange(Amt.getStart(),
2441                                 Amt.getConstantLength()))
2442      : FixItHint();
2443
2444  EmitFormatDiagnostic(S.PDiag(diag::warn_printf_nonsensical_optional_amount)
2445                         << type << CS.toString(),
2446                       getLocationOfByte(Amt.getStart()),
2447                       /*IsStringLocation*/true,
2448                       getSpecifierRange(startSpecifier, specifierLen),
2449                       fixit);
2450}
2451
2452void CheckPrintfHandler::HandleFlag(const analyze_printf::PrintfSpecifier &FS,
2453                                    const analyze_printf::OptionalFlag &flag,
2454                                    const char *startSpecifier,
2455                                    unsigned specifierLen) {
2456  // Warn about pointless flag with a fixit removal.
2457  const analyze_printf::PrintfConversionSpecifier &CS =
2458    FS.getConversionSpecifier();
2459  EmitFormatDiagnostic(S.PDiag(diag::warn_printf_nonsensical_flag)
2460                         << flag.toString() << CS.toString(),
2461                       getLocationOfByte(flag.getPosition()),
2462                       /*IsStringLocation*/true,
2463                       getSpecifierRange(startSpecifier, specifierLen),
2464                       FixItHint::CreateRemoval(
2465                         getSpecifierRange(flag.getPosition(), 1)));
2466}
2467
2468void CheckPrintfHandler::HandleIgnoredFlag(
2469                                const analyze_printf::PrintfSpecifier &FS,
2470                                const analyze_printf::OptionalFlag &ignoredFlag,
2471                                const analyze_printf::OptionalFlag &flag,
2472                                const char *startSpecifier,
2473                                unsigned specifierLen) {
2474  // Warn about ignored flag with a fixit removal.
2475  EmitFormatDiagnostic(S.PDiag(diag::warn_printf_ignored_flag)
2476                         << ignoredFlag.toString() << flag.toString(),
2477                       getLocationOfByte(ignoredFlag.getPosition()),
2478                       /*IsStringLocation*/true,
2479                       getSpecifierRange(startSpecifier, specifierLen),
2480                       FixItHint::CreateRemoval(
2481                         getSpecifierRange(ignoredFlag.getPosition(), 1)));
2482}
2483
2484// Determines if the specified is a C++ class or struct containing
2485// a member with the specified name and kind (e.g. a CXXMethodDecl named
2486// "c_str()").
2487template<typename MemberKind>
2488static llvm::SmallPtrSet<MemberKind*, 1>
2489CXXRecordMembersNamed(StringRef Name, Sema &S, QualType Ty) {
2490  const RecordType *RT = Ty->getAs<RecordType>();
2491  llvm::SmallPtrSet<MemberKind*, 1> Results;
2492
2493  if (!RT)
2494    return Results;
2495  const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(RT->getDecl());
2496  if (!RD)
2497    return Results;
2498
2499  LookupResult R(S, &S.PP.getIdentifierTable().get(Name), SourceLocation(),
2500                 Sema::LookupMemberName);
2501
2502  // We just need to include all members of the right kind turned up by the
2503  // filter, at this point.
2504  if (S.LookupQualifiedName(R, RT->getDecl()))
2505    for (LookupResult::iterator I = R.begin(), E = R.end(); I != E; ++I) {
2506      NamedDecl *decl = (*I)->getUnderlyingDecl();
2507      if (MemberKind *FK = dyn_cast<MemberKind>(decl))
2508        Results.insert(FK);
2509    }
2510  return Results;
2511}
2512
2513// Check if a (w)string was passed when a (w)char* was needed, and offer a
2514// better diagnostic if so. AT is assumed to be valid.
2515// Returns true when a c_str() conversion method is found.
2516bool CheckPrintfHandler::checkForCStrMembers(
2517    const analyze_printf::ArgType &AT, const Expr *E,
2518    const CharSourceRange &CSR) {
2519  typedef llvm::SmallPtrSet<CXXMethodDecl*, 1> MethodSet;
2520
2521  MethodSet Results =
2522      CXXRecordMembersNamed<CXXMethodDecl>("c_str", S, E->getType());
2523
2524  for (MethodSet::iterator MI = Results.begin(), ME = Results.end();
2525       MI != ME; ++MI) {
2526    const CXXMethodDecl *Method = *MI;
2527    if (Method->getNumParams() == 0 &&
2528          AT.matchesType(S.Context, Method->getResultType())) {
2529      // FIXME: Suggest parens if the expression needs them.
2530      SourceLocation EndLoc =
2531          S.getPreprocessor().getLocForEndOfToken(E->getLocEnd());
2532      S.Diag(E->getLocStart(), diag::note_printf_c_str)
2533          << "c_str()"
2534          << FixItHint::CreateInsertion(EndLoc, ".c_str()");
2535      return true;
2536    }
2537  }
2538
2539  return false;
2540}
2541
2542bool
2543CheckPrintfHandler::HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier
2544                                            &FS,
2545                                          const char *startSpecifier,
2546                                          unsigned specifierLen) {
2547
2548  using namespace analyze_format_string;
2549  using namespace analyze_printf;
2550  const PrintfConversionSpecifier &CS = FS.getConversionSpecifier();
2551
2552  if (FS.consumesDataArgument()) {
2553    if (atFirstArg) {
2554        atFirstArg = false;
2555        usesPositionalArgs = FS.usesPositionalArg();
2556    }
2557    else if (usesPositionalArgs != FS.usesPositionalArg()) {
2558      HandlePositionalNonpositionalArgs(getLocationOfByte(CS.getStart()),
2559                                        startSpecifier, specifierLen);
2560      return false;
2561    }
2562  }
2563
2564  // First check if the field width, precision, and conversion specifier
2565  // have matching data arguments.
2566  if (!HandleAmount(FS.getFieldWidth(), /* field width */ 0,
2567                    startSpecifier, specifierLen)) {
2568    return false;
2569  }
2570
2571  if (!HandleAmount(FS.getPrecision(), /* precision */ 1,
2572                    startSpecifier, specifierLen)) {
2573    return false;
2574  }
2575
2576  if (!CS.consumesDataArgument()) {
2577    // FIXME: Technically specifying a precision or field width here
2578    // makes no sense.  Worth issuing a warning at some point.
2579    return true;
2580  }
2581
2582  // Consume the argument.
2583  unsigned argIndex = FS.getArgIndex();
2584  if (argIndex < NumDataArgs) {
2585    // The check to see if the argIndex is valid will come later.
2586    // We set the bit here because we may exit early from this
2587    // function if we encounter some other error.
2588    CoveredArgs.set(argIndex);
2589  }
2590
2591  // Check for using an Objective-C specific conversion specifier
2592  // in a non-ObjC literal.
2593  if (!ObjCContext && CS.isObjCArg()) {
2594    return HandleInvalidPrintfConversionSpecifier(FS, startSpecifier,
2595                                                  specifierLen);
2596  }
2597
2598  // Check for invalid use of field width
2599  if (!FS.hasValidFieldWidth()) {
2600    HandleInvalidAmount(FS, FS.getFieldWidth(), /* field width */ 0,
2601        startSpecifier, specifierLen);
2602  }
2603
2604  // Check for invalid use of precision
2605  if (!FS.hasValidPrecision()) {
2606    HandleInvalidAmount(FS, FS.getPrecision(), /* precision */ 1,
2607        startSpecifier, specifierLen);
2608  }
2609
2610  // Check each flag does not conflict with any other component.
2611  if (!FS.hasValidThousandsGroupingPrefix())
2612    HandleFlag(FS, FS.hasThousandsGrouping(), startSpecifier, specifierLen);
2613  if (!FS.hasValidLeadingZeros())
2614    HandleFlag(FS, FS.hasLeadingZeros(), startSpecifier, specifierLen);
2615  if (!FS.hasValidPlusPrefix())
2616    HandleFlag(FS, FS.hasPlusPrefix(), startSpecifier, specifierLen);
2617  if (!FS.hasValidSpacePrefix())
2618    HandleFlag(FS, FS.hasSpacePrefix(), startSpecifier, specifierLen);
2619  if (!FS.hasValidAlternativeForm())
2620    HandleFlag(FS, FS.hasAlternativeForm(), startSpecifier, specifierLen);
2621  if (!FS.hasValidLeftJustified())
2622    HandleFlag(FS, FS.isLeftJustified(), startSpecifier, specifierLen);
2623
2624  // Check that flags are not ignored by another flag
2625  if (FS.hasSpacePrefix() && FS.hasPlusPrefix()) // ' ' ignored by '+'
2626    HandleIgnoredFlag(FS, FS.hasSpacePrefix(), FS.hasPlusPrefix(),
2627        startSpecifier, specifierLen);
2628  if (FS.hasLeadingZeros() && FS.isLeftJustified()) // '0' ignored by '-'
2629    HandleIgnoredFlag(FS, FS.hasLeadingZeros(), FS.isLeftJustified(),
2630            startSpecifier, specifierLen);
2631
2632  // Check the length modifier is valid with the given conversion specifier.
2633  if (!FS.hasValidLengthModifier(S.getASTContext().getTargetInfo()))
2634    HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen,
2635                                diag::warn_format_nonsensical_length);
2636  else if (!FS.hasStandardLengthModifier())
2637    HandleNonStandardLengthModifier(FS, startSpecifier, specifierLen);
2638  else if (!FS.hasStandardLengthConversionCombination())
2639    HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen,
2640                                diag::warn_format_non_standard_conversion_spec);
2641
2642  if (!FS.hasStandardConversionSpecifier(S.getLangOpts()))
2643    HandleNonStandardConversionSpecifier(CS, startSpecifier, specifierLen);
2644
2645  // The remaining checks depend on the data arguments.
2646  if (HasVAListArg)
2647    return true;
2648
2649  if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex))
2650    return false;
2651
2652  const Expr *Arg = getDataArg(argIndex);
2653  if (!Arg)
2654    return true;
2655
2656  return checkFormatExpr(FS, startSpecifier, specifierLen, Arg);
2657}
2658
2659static bool requiresParensToAddCast(const Expr *E) {
2660  // FIXME: We should have a general way to reason about operator
2661  // precedence and whether parens are actually needed here.
2662  // Take care of a few common cases where they aren't.
2663  const Expr *Inside = E->IgnoreImpCasts();
2664  if (const PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(Inside))
2665    Inside = POE->getSyntacticForm()->IgnoreImpCasts();
2666
2667  switch (Inside->getStmtClass()) {
2668  case Stmt::ArraySubscriptExprClass:
2669  case Stmt::CallExprClass:
2670  case Stmt::DeclRefExprClass:
2671  case Stmt::MemberExprClass:
2672  case Stmt::ObjCIvarRefExprClass:
2673  case Stmt::ObjCMessageExprClass:
2674  case Stmt::ObjCPropertyRefExprClass:
2675  case Stmt::ParenExprClass:
2676  case Stmt::UnaryOperatorClass:
2677    return false;
2678  default:
2679    return true;
2680  }
2681}
2682
2683bool
2684CheckPrintfHandler::checkFormatExpr(const analyze_printf::PrintfSpecifier &FS,
2685                                    const char *StartSpecifier,
2686                                    unsigned SpecifierLen,
2687                                    const Expr *E) {
2688  using namespace analyze_format_string;
2689  using namespace analyze_printf;
2690  // Now type check the data expression that matches the
2691  // format specifier.
2692  const analyze_printf::ArgType &AT = FS.getArgType(S.Context,
2693                                                    ObjCContext);
2694  if (!AT.isValid())
2695    return true;
2696
2697  QualType IntendedTy = E->getType();
2698  if (AT.matchesType(S.Context, IntendedTy))
2699    return true;
2700
2701  // Look through argument promotions for our error message's reported type.
2702  // This includes the integral and floating promotions, but excludes array
2703  // and function pointer decay; seeing that an argument intended to be a
2704  // string has type 'char [6]' is probably more confusing than 'char *'.
2705  if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) {
2706    if (ICE->getCastKind() == CK_IntegralCast ||
2707        ICE->getCastKind() == CK_FloatingCast) {
2708      E = ICE->getSubExpr();
2709      IntendedTy = E->getType();
2710
2711      // Check if we didn't match because of an implicit cast from a 'char'
2712      // or 'short' to an 'int'.  This is done because printf is a varargs
2713      // function.
2714      if (ICE->getType() == S.Context.IntTy ||
2715          ICE->getType() == S.Context.UnsignedIntTy) {
2716        // All further checking is done on the subexpression.
2717        if (AT.matchesType(S.Context, IntendedTy))
2718          return true;
2719      }
2720    }
2721  }
2722
2723  if (S.Context.getTargetInfo().getTriple().isOSDarwin()) {
2724    // Special-case some of Darwin's platform-independence types.
2725    if (const TypedefType *UserTy = IntendedTy->getAs<TypedefType>()) {
2726      StringRef Name = UserTy->getDecl()->getName();
2727      IntendedTy = llvm::StringSwitch<QualType>(Name)
2728        .Case("NSInteger", S.Context.LongTy)
2729        .Case("NSUInteger", S.Context.UnsignedLongTy)
2730        .Case("SInt32", S.Context.IntTy)
2731        .Case("UInt32", S.Context.UnsignedIntTy)
2732        .Default(IntendedTy);
2733    }
2734  }
2735
2736  // We may be able to offer a FixItHint if it is a supported type.
2737  PrintfSpecifier fixedFS = FS;
2738  bool success = fixedFS.fixType(IntendedTy, S.getLangOpts(),
2739                                 S.Context, ObjCContext);
2740
2741  if (success) {
2742    // Get the fix string from the fixed format specifier
2743    SmallString<16> buf;
2744    llvm::raw_svector_ostream os(buf);
2745    fixedFS.toString(os);
2746
2747    CharSourceRange SpecRange = getSpecifierRange(StartSpecifier, SpecifierLen);
2748
2749    if (IntendedTy != E->getType()) {
2750      // The canonical type for formatting this value is different from the
2751      // actual type of the expression. (This occurs, for example, with Darwin's
2752      // NSInteger on 32-bit platforms, where it is typedef'd as 'int', but
2753      // should be printed as 'long' for 64-bit compatibility.)
2754      // Rather than emitting a normal format/argument mismatch, we want to
2755      // add a cast to the recommended type (and correct the format string
2756      // if necessary).
2757      SmallString<16> CastBuf;
2758      llvm::raw_svector_ostream CastFix(CastBuf);
2759      CastFix << "(";
2760      IntendedTy.print(CastFix, S.Context.getPrintingPolicy());
2761      CastFix << ")";
2762
2763      SmallVector<FixItHint,4> Hints;
2764      if (!AT.matchesType(S.Context, IntendedTy))
2765        Hints.push_back(FixItHint::CreateReplacement(SpecRange, os.str()));
2766
2767      if (const CStyleCastExpr *CCast = dyn_cast<CStyleCastExpr>(E)) {
2768        // If there's already a cast present, just replace it.
2769        SourceRange CastRange(CCast->getLParenLoc(), CCast->getRParenLoc());
2770        Hints.push_back(FixItHint::CreateReplacement(CastRange, CastFix.str()));
2771
2772      } else if (!requiresParensToAddCast(E)) {
2773        // If the expression has high enough precedence,
2774        // just write the C-style cast.
2775        Hints.push_back(FixItHint::CreateInsertion(E->getLocStart(),
2776                                                   CastFix.str()));
2777      } else {
2778        // Otherwise, add parens around the expression as well as the cast.
2779        CastFix << "(";
2780        Hints.push_back(FixItHint::CreateInsertion(E->getLocStart(),
2781                                                   CastFix.str()));
2782
2783        SourceLocation After = S.PP.getLocForEndOfToken(E->getLocEnd());
2784        Hints.push_back(FixItHint::CreateInsertion(After, ")"));
2785      }
2786
2787      // We extract the name from the typedef because we don't want to show
2788      // the underlying type in the diagnostic.
2789      const TypedefType *UserTy = cast<TypedefType>(E->getType());
2790      StringRef Name = UserTy->getDecl()->getName();
2791
2792      // Finally, emit the diagnostic.
2793      EmitFormatDiagnostic(S.PDiag(diag::warn_format_argument_needs_cast)
2794                             << Name << IntendedTy
2795                             << E->getSourceRange(),
2796                           E->getLocStart(), /*IsStringLocation=*/false,
2797                           SpecRange, Hints);
2798    } else {
2799      EmitFormatDiagnostic(
2800        S.PDiag(diag::warn_printf_conversion_argument_type_mismatch)
2801          << AT.getRepresentativeTypeName(S.Context) << IntendedTy
2802          << E->getSourceRange(),
2803        E->getLocStart(),
2804        /*IsStringLocation*/false,
2805        SpecRange,
2806        FixItHint::CreateReplacement(SpecRange, os.str()));
2807    }
2808  } else {
2809    const CharSourceRange &CSR = getSpecifierRange(StartSpecifier,
2810                                                   SpecifierLen);
2811    // Since the warning for passing non-POD types to variadic functions
2812    // was deferred until now, we emit a warning for non-POD
2813    // arguments here.
2814    if (S.isValidVarArgType(E->getType()) == Sema::VAK_Invalid) {
2815      unsigned DiagKind;
2816      if (E->getType()->isObjCObjectType())
2817        DiagKind = diag::err_cannot_pass_objc_interface_to_vararg_format;
2818      else
2819        DiagKind = diag::warn_non_pod_vararg_with_format_string;
2820
2821      EmitFormatDiagnostic(
2822        S.PDiag(DiagKind)
2823          << S.getLangOpts().CPlusPlus0x
2824          << E->getType()
2825          << CallType
2826          << AT.getRepresentativeTypeName(S.Context)
2827          << CSR
2828          << E->getSourceRange(),
2829        E->getLocStart(), /*IsStringLocation*/false, CSR);
2830
2831      checkForCStrMembers(AT, E, CSR);
2832    } else
2833      EmitFormatDiagnostic(
2834        S.PDiag(diag::warn_printf_conversion_argument_type_mismatch)
2835          << AT.getRepresentativeTypeName(S.Context) << E->getType()
2836          << CSR
2837          << E->getSourceRange(),
2838        E->getLocStart(), /*IsStringLocation*/false, CSR);
2839  }
2840
2841  return true;
2842}
2843
2844//===--- CHECK: Scanf format string checking ------------------------------===//
2845
2846namespace {
2847class CheckScanfHandler : public CheckFormatHandler {
2848public:
2849  CheckScanfHandler(Sema &s, const StringLiteral *fexpr,
2850                    const Expr *origFormatExpr, unsigned firstDataArg,
2851                    unsigned numDataArgs, const char *beg, bool hasVAListArg,
2852                    Expr **Args, unsigned NumArgs,
2853                    unsigned formatIdx, bool inFunctionCall,
2854                    Sema::VariadicCallType CallType)
2855  : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg,
2856                       numDataArgs, beg, hasVAListArg,
2857                       Args, NumArgs, formatIdx, inFunctionCall, CallType)
2858  {}
2859
2860  bool HandleScanfSpecifier(const analyze_scanf::ScanfSpecifier &FS,
2861                            const char *startSpecifier,
2862                            unsigned specifierLen);
2863
2864  bool HandleInvalidScanfConversionSpecifier(
2865          const analyze_scanf::ScanfSpecifier &FS,
2866          const char *startSpecifier,
2867          unsigned specifierLen);
2868
2869  void HandleIncompleteScanList(const char *start, const char *end);
2870};
2871}
2872
2873void CheckScanfHandler::HandleIncompleteScanList(const char *start,
2874                                                 const char *end) {
2875  EmitFormatDiagnostic(S.PDiag(diag::warn_scanf_scanlist_incomplete),
2876                       getLocationOfByte(end), /*IsStringLocation*/true,
2877                       getSpecifierRange(start, end - start));
2878}
2879
2880bool CheckScanfHandler::HandleInvalidScanfConversionSpecifier(
2881                                        const analyze_scanf::ScanfSpecifier &FS,
2882                                        const char *startSpecifier,
2883                                        unsigned specifierLen) {
2884
2885  const analyze_scanf::ScanfConversionSpecifier &CS =
2886    FS.getConversionSpecifier();
2887
2888  return HandleInvalidConversionSpecifier(FS.getArgIndex(),
2889                                          getLocationOfByte(CS.getStart()),
2890                                          startSpecifier, specifierLen,
2891                                          CS.getStart(), CS.getLength());
2892}
2893
2894bool CheckScanfHandler::HandleScanfSpecifier(
2895                                       const analyze_scanf::ScanfSpecifier &FS,
2896                                       const char *startSpecifier,
2897                                       unsigned specifierLen) {
2898
2899  using namespace analyze_scanf;
2900  using namespace analyze_format_string;
2901
2902  const ScanfConversionSpecifier &CS = FS.getConversionSpecifier();
2903
2904  // Handle case where '%' and '*' don't consume an argument.  These shouldn't
2905  // be used to decide if we are using positional arguments consistently.
2906  if (FS.consumesDataArgument()) {
2907    if (atFirstArg) {
2908      atFirstArg = false;
2909      usesPositionalArgs = FS.usesPositionalArg();
2910    }
2911    else if (usesPositionalArgs != FS.usesPositionalArg()) {
2912      HandlePositionalNonpositionalArgs(getLocationOfByte(CS.getStart()),
2913                                        startSpecifier, specifierLen);
2914      return false;
2915    }
2916  }
2917
2918  // Check if the field with is non-zero.
2919  const OptionalAmount &Amt = FS.getFieldWidth();
2920  if (Amt.getHowSpecified() == OptionalAmount::Constant) {
2921    if (Amt.getConstantAmount() == 0) {
2922      const CharSourceRange &R = getSpecifierRange(Amt.getStart(),
2923                                                   Amt.getConstantLength());
2924      EmitFormatDiagnostic(S.PDiag(diag::warn_scanf_nonzero_width),
2925                           getLocationOfByte(Amt.getStart()),
2926                           /*IsStringLocation*/true, R,
2927                           FixItHint::CreateRemoval(R));
2928    }
2929  }
2930
2931  if (!FS.consumesDataArgument()) {
2932    // FIXME: Technically specifying a precision or field width here
2933    // makes no sense.  Worth issuing a warning at some point.
2934    return true;
2935  }
2936
2937  // Consume the argument.
2938  unsigned argIndex = FS.getArgIndex();
2939  if (argIndex < NumDataArgs) {
2940      // The check to see if the argIndex is valid will come later.
2941      // We set the bit here because we may exit early from this
2942      // function if we encounter some other error.
2943    CoveredArgs.set(argIndex);
2944  }
2945
2946  // Check the length modifier is valid with the given conversion specifier.
2947  if (!FS.hasValidLengthModifier(S.getASTContext().getTargetInfo()))
2948    HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen,
2949                                diag::warn_format_nonsensical_length);
2950  else if (!FS.hasStandardLengthModifier())
2951    HandleNonStandardLengthModifier(FS, startSpecifier, specifierLen);
2952  else if (!FS.hasStandardLengthConversionCombination())
2953    HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen,
2954                                diag::warn_format_non_standard_conversion_spec);
2955
2956  if (!FS.hasStandardConversionSpecifier(S.getLangOpts()))
2957    HandleNonStandardConversionSpecifier(CS, startSpecifier, specifierLen);
2958
2959  // The remaining checks depend on the data arguments.
2960  if (HasVAListArg)
2961    return true;
2962
2963  if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex))
2964    return false;
2965
2966  // Check that the argument type matches the format specifier.
2967  const Expr *Ex = getDataArg(argIndex);
2968  if (!Ex)
2969    return true;
2970
2971  const analyze_format_string::ArgType &AT = FS.getArgType(S.Context);
2972  if (AT.isValid() && !AT.matchesType(S.Context, Ex->getType())) {
2973    ScanfSpecifier fixedFS = FS;
2974    bool success = fixedFS.fixType(Ex->getType(), S.getLangOpts(),
2975                                   S.Context);
2976
2977    if (success) {
2978      // Get the fix string from the fixed format specifier.
2979      SmallString<128> buf;
2980      llvm::raw_svector_ostream os(buf);
2981      fixedFS.toString(os);
2982
2983      EmitFormatDiagnostic(
2984        S.PDiag(diag::warn_printf_conversion_argument_type_mismatch)
2985          << AT.getRepresentativeTypeName(S.Context) << Ex->getType()
2986          << Ex->getSourceRange(),
2987        Ex->getLocStart(),
2988        /*IsStringLocation*/false,
2989        getSpecifierRange(startSpecifier, specifierLen),
2990        FixItHint::CreateReplacement(
2991          getSpecifierRange(startSpecifier, specifierLen),
2992          os.str()));
2993    } else {
2994      EmitFormatDiagnostic(
2995        S.PDiag(diag::warn_printf_conversion_argument_type_mismatch)
2996          << AT.getRepresentativeTypeName(S.Context) << Ex->getType()
2997          << Ex->getSourceRange(),
2998        Ex->getLocStart(),
2999        /*IsStringLocation*/false,
3000        getSpecifierRange(startSpecifier, specifierLen));
3001    }
3002  }
3003
3004  return true;
3005}
3006
3007void Sema::CheckFormatString(const StringLiteral *FExpr,
3008                             const Expr *OrigFormatExpr,
3009                             Expr **Args, unsigned NumArgs,
3010                             bool HasVAListArg, unsigned format_idx,
3011                             unsigned firstDataArg, FormatStringType Type,
3012                             bool inFunctionCall, VariadicCallType CallType) {
3013
3014  // CHECK: is the format string a wide literal?
3015  if (!FExpr->isAscii() && !FExpr->isUTF8()) {
3016    CheckFormatHandler::EmitFormatDiagnostic(
3017      *this, inFunctionCall, Args[format_idx],
3018      PDiag(diag::warn_format_string_is_wide_literal), FExpr->getLocStart(),
3019      /*IsStringLocation*/true, OrigFormatExpr->getSourceRange());
3020    return;
3021  }
3022
3023  // Str - The format string.  NOTE: this is NOT null-terminated!
3024  StringRef StrRef = FExpr->getString();
3025  const char *Str = StrRef.data();
3026  unsigned StrLen = StrRef.size();
3027  const unsigned numDataArgs = NumArgs - firstDataArg;
3028
3029  // CHECK: empty format string?
3030  if (StrLen == 0 && numDataArgs > 0) {
3031    CheckFormatHandler::EmitFormatDiagnostic(
3032      *this, inFunctionCall, Args[format_idx],
3033      PDiag(diag::warn_empty_format_string), FExpr->getLocStart(),
3034      /*IsStringLocation*/true, OrigFormatExpr->getSourceRange());
3035    return;
3036  }
3037
3038  if (Type == FST_Printf || Type == FST_NSString) {
3039    CheckPrintfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg,
3040                         numDataArgs, (Type == FST_NSString),
3041                         Str, HasVAListArg, Args, NumArgs, format_idx,
3042                         inFunctionCall, CallType);
3043
3044    if (!analyze_format_string::ParsePrintfString(H, Str, Str + StrLen,
3045                                                  getLangOpts(),
3046                                                  Context.getTargetInfo()))
3047      H.DoneProcessing();
3048  } else if (Type == FST_Scanf) {
3049    CheckScanfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg, numDataArgs,
3050                        Str, HasVAListArg, Args, NumArgs, format_idx,
3051                        inFunctionCall, CallType);
3052
3053    if (!analyze_format_string::ParseScanfString(H, Str, Str + StrLen,
3054                                                 getLangOpts(),
3055                                                 Context.getTargetInfo()))
3056      H.DoneProcessing();
3057  } // TODO: handle other formats
3058}
3059
3060//===--- CHECK: Standard memory functions ---------------------------------===//
3061
3062/// \brief Determine whether the given type is a dynamic class type (e.g.,
3063/// whether it has a vtable).
3064static bool isDynamicClassType(QualType T) {
3065  if (CXXRecordDecl *Record = T->getAsCXXRecordDecl())
3066    if (CXXRecordDecl *Definition = Record->getDefinition())
3067      if (Definition->isDynamicClass())
3068        return true;
3069
3070  return false;
3071}
3072
3073/// \brief If E is a sizeof expression, returns its argument expression,
3074/// otherwise returns NULL.
3075static const Expr *getSizeOfExprArg(const Expr* E) {
3076  if (const UnaryExprOrTypeTraitExpr *SizeOf =
3077      dyn_cast<UnaryExprOrTypeTraitExpr>(E))
3078    if (SizeOf->getKind() == clang::UETT_SizeOf && !SizeOf->isArgumentType())
3079      return SizeOf->getArgumentExpr()->IgnoreParenImpCasts();
3080
3081  return 0;
3082}
3083
3084/// \brief If E is a sizeof expression, returns its argument type.
3085static QualType getSizeOfArgType(const Expr* E) {
3086  if (const UnaryExprOrTypeTraitExpr *SizeOf =
3087      dyn_cast<UnaryExprOrTypeTraitExpr>(E))
3088    if (SizeOf->getKind() == clang::UETT_SizeOf)
3089      return SizeOf->getTypeOfArgument();
3090
3091  return QualType();
3092}
3093
3094/// \brief Check for dangerous or invalid arguments to memset().
3095///
3096/// This issues warnings on known problematic, dangerous or unspecified
3097/// arguments to the standard 'memset', 'memcpy', 'memmove', and 'memcmp'
3098/// function calls.
3099///
3100/// \param Call The call expression to diagnose.
3101void Sema::CheckMemaccessArguments(const CallExpr *Call,
3102                                   unsigned BId,
3103                                   IdentifierInfo *FnName) {
3104  assert(BId != 0);
3105
3106  // It is possible to have a non-standard definition of memset.  Validate
3107  // we have enough arguments, and if not, abort further checking.
3108  unsigned ExpectedNumArgs = (BId == Builtin::BIstrndup ? 2 : 3);
3109  if (Call->getNumArgs() < ExpectedNumArgs)
3110    return;
3111
3112  unsigned LastArg = (BId == Builtin::BImemset ||
3113                      BId == Builtin::BIstrndup ? 1 : 2);
3114  unsigned LenArg = (BId == Builtin::BIstrndup ? 1 : 2);
3115  const Expr *LenExpr = Call->getArg(LenArg)->IgnoreParenImpCasts();
3116
3117  // We have special checking when the length is a sizeof expression.
3118  QualType SizeOfArgTy = getSizeOfArgType(LenExpr);
3119  const Expr *SizeOfArg = getSizeOfExprArg(LenExpr);
3120  llvm::FoldingSetNodeID SizeOfArgID;
3121
3122  for (unsigned ArgIdx = 0; ArgIdx != LastArg; ++ArgIdx) {
3123    const Expr *Dest = Call->getArg(ArgIdx)->IgnoreParenImpCasts();
3124    SourceRange ArgRange = Call->getArg(ArgIdx)->getSourceRange();
3125
3126    QualType DestTy = Dest->getType();
3127    if (const PointerType *DestPtrTy = DestTy->getAs<PointerType>()) {
3128      QualType PointeeTy = DestPtrTy->getPointeeType();
3129
3130      // Never warn about void type pointers. This can be used to suppress
3131      // false positives.
3132      if (PointeeTy->isVoidType())
3133        continue;
3134
3135      // Catch "memset(p, 0, sizeof(p))" -- needs to be sizeof(*p). Do this by
3136      // actually comparing the expressions for equality. Because computing the
3137      // expression IDs can be expensive, we only do this if the diagnostic is
3138      // enabled.
3139      if (SizeOfArg &&
3140          Diags.getDiagnosticLevel(diag::warn_sizeof_pointer_expr_memaccess,
3141                                   SizeOfArg->getExprLoc())) {
3142        // We only compute IDs for expressions if the warning is enabled, and
3143        // cache the sizeof arg's ID.
3144        if (SizeOfArgID == llvm::FoldingSetNodeID())
3145          SizeOfArg->Profile(SizeOfArgID, Context, true);
3146        llvm::FoldingSetNodeID DestID;
3147        Dest->Profile(DestID, Context, true);
3148        if (DestID == SizeOfArgID) {
3149          // TODO: For strncpy() and friends, this could suggest sizeof(dst)
3150          //       over sizeof(src) as well.
3151          unsigned ActionIdx = 0; // Default is to suggest dereferencing.
3152          StringRef ReadableName = FnName->getName();
3153
3154          if (const UnaryOperator *UnaryOp = dyn_cast<UnaryOperator>(Dest))
3155            if (UnaryOp->getOpcode() == UO_AddrOf)
3156              ActionIdx = 1; // If its an address-of operator, just remove it.
3157          if (Context.getTypeSize(PointeeTy) == Context.getCharWidth())
3158            ActionIdx = 2; // If the pointee's size is sizeof(char),
3159                           // suggest an explicit length.
3160
3161          // If the function is defined as a builtin macro, do not show macro
3162          // expansion.
3163          SourceLocation SL = SizeOfArg->getExprLoc();
3164          SourceRange DSR = Dest->getSourceRange();
3165          SourceRange SSR = SizeOfArg->getSourceRange();
3166          SourceManager &SM  = PP.getSourceManager();
3167
3168          if (SM.isMacroArgExpansion(SL)) {
3169            ReadableName = Lexer::getImmediateMacroName(SL, SM, LangOpts);
3170            SL = SM.getSpellingLoc(SL);
3171            DSR = SourceRange(SM.getSpellingLoc(DSR.getBegin()),
3172                             SM.getSpellingLoc(DSR.getEnd()));
3173            SSR = SourceRange(SM.getSpellingLoc(SSR.getBegin()),
3174                             SM.getSpellingLoc(SSR.getEnd()));
3175          }
3176
3177          DiagRuntimeBehavior(SL, SizeOfArg,
3178                              PDiag(diag::warn_sizeof_pointer_expr_memaccess)
3179                                << ReadableName
3180                                << PointeeTy
3181                                << DestTy
3182                                << DSR
3183                                << SSR);
3184          DiagRuntimeBehavior(SL, SizeOfArg,
3185                         PDiag(diag::warn_sizeof_pointer_expr_memaccess_note)
3186                                << ActionIdx
3187                                << SSR);
3188
3189          break;
3190        }
3191      }
3192
3193      // Also check for cases where the sizeof argument is the exact same
3194      // type as the memory argument, and where it points to a user-defined
3195      // record type.
3196      if (SizeOfArgTy != QualType()) {
3197        if (PointeeTy->isRecordType() &&
3198            Context.typesAreCompatible(SizeOfArgTy, DestTy)) {
3199          DiagRuntimeBehavior(LenExpr->getExprLoc(), Dest,
3200                              PDiag(diag::warn_sizeof_pointer_type_memaccess)
3201                                << FnName << SizeOfArgTy << ArgIdx
3202                                << PointeeTy << Dest->getSourceRange()
3203                                << LenExpr->getSourceRange());
3204          break;
3205        }
3206      }
3207
3208      // Always complain about dynamic classes.
3209      if (isDynamicClassType(PointeeTy)) {
3210
3211        unsigned OperationType = 0;
3212        // "overwritten" if we're warning about the destination for any call
3213        // but memcmp; otherwise a verb appropriate to the call.
3214        if (ArgIdx != 0 || BId == Builtin::BImemcmp) {
3215          if (BId == Builtin::BImemcpy)
3216            OperationType = 1;
3217          else if(BId == Builtin::BImemmove)
3218            OperationType = 2;
3219          else if (BId == Builtin::BImemcmp)
3220            OperationType = 3;
3221        }
3222
3223        DiagRuntimeBehavior(
3224          Dest->getExprLoc(), Dest,
3225          PDiag(diag::warn_dyn_class_memaccess)
3226            << (BId == Builtin::BImemcmp ? ArgIdx + 2 : ArgIdx)
3227            << FnName << PointeeTy
3228            << OperationType
3229            << Call->getCallee()->getSourceRange());
3230      } else if (PointeeTy.hasNonTrivialObjCLifetime() &&
3231               BId != Builtin::BImemset)
3232        DiagRuntimeBehavior(
3233          Dest->getExprLoc(), Dest,
3234          PDiag(diag::warn_arc_object_memaccess)
3235            << ArgIdx << FnName << PointeeTy
3236            << Call->getCallee()->getSourceRange());
3237      else
3238        continue;
3239
3240      DiagRuntimeBehavior(
3241        Dest->getExprLoc(), Dest,
3242        PDiag(diag::note_bad_memaccess_silence)
3243          << FixItHint::CreateInsertion(ArgRange.getBegin(), "(void*)"));
3244      break;
3245    }
3246  }
3247}
3248
3249// A little helper routine: ignore addition and subtraction of integer literals.
3250// This intentionally does not ignore all integer constant expressions because
3251// we don't want to remove sizeof().
3252static const Expr *ignoreLiteralAdditions(const Expr *Ex, ASTContext &Ctx) {
3253  Ex = Ex->IgnoreParenCasts();
3254
3255  for (;;) {
3256    const BinaryOperator * BO = dyn_cast<BinaryOperator>(Ex);
3257    if (!BO || !BO->isAdditiveOp())
3258      break;
3259
3260    const Expr *RHS = BO->getRHS()->IgnoreParenCasts();
3261    const Expr *LHS = BO->getLHS()->IgnoreParenCasts();
3262
3263    if (isa<IntegerLiteral>(RHS))
3264      Ex = LHS;
3265    else if (isa<IntegerLiteral>(LHS))
3266      Ex = RHS;
3267    else
3268      break;
3269  }
3270
3271  return Ex;
3272}
3273
3274static bool isConstantSizeArrayWithMoreThanOneElement(QualType Ty,
3275                                                      ASTContext &Context) {
3276  // Only handle constant-sized or VLAs, but not flexible members.
3277  if (const ConstantArrayType *CAT = Context.getAsConstantArrayType(Ty)) {
3278    // Only issue the FIXIT for arrays of size > 1.
3279    if (CAT->getSize().getSExtValue() <= 1)
3280      return false;
3281  } else if (!Ty->isVariableArrayType()) {
3282    return false;
3283  }
3284  return true;
3285}
3286
3287// Warn if the user has made the 'size' argument to strlcpy or strlcat
3288// be the size of the source, instead of the destination.
3289void Sema::CheckStrlcpycatArguments(const CallExpr *Call,
3290                                    IdentifierInfo *FnName) {
3291
3292  // Don't crash if the user has the wrong number of arguments
3293  if (Call->getNumArgs() != 3)
3294    return;
3295
3296  const Expr *SrcArg = ignoreLiteralAdditions(Call->getArg(1), Context);
3297  const Expr *SizeArg = ignoreLiteralAdditions(Call->getArg(2), Context);
3298  const Expr *CompareWithSrc = NULL;
3299
3300  // Look for 'strlcpy(dst, x, sizeof(x))'
3301  if (const Expr *Ex = getSizeOfExprArg(SizeArg))
3302    CompareWithSrc = Ex;
3303  else {
3304    // Look for 'strlcpy(dst, x, strlen(x))'
3305    if (const CallExpr *SizeCall = dyn_cast<CallExpr>(SizeArg)) {
3306      if (SizeCall->isBuiltinCall() == Builtin::BIstrlen
3307          && SizeCall->getNumArgs() == 1)
3308        CompareWithSrc = ignoreLiteralAdditions(SizeCall->getArg(0), Context);
3309    }
3310  }
3311
3312  if (!CompareWithSrc)
3313    return;
3314
3315  // Determine if the argument to sizeof/strlen is equal to the source
3316  // argument.  In principle there's all kinds of things you could do
3317  // here, for instance creating an == expression and evaluating it with
3318  // EvaluateAsBooleanCondition, but this uses a more direct technique:
3319  const DeclRefExpr *SrcArgDRE = dyn_cast<DeclRefExpr>(SrcArg);
3320  if (!SrcArgDRE)
3321    return;
3322
3323  const DeclRefExpr *CompareWithSrcDRE = dyn_cast<DeclRefExpr>(CompareWithSrc);
3324  if (!CompareWithSrcDRE ||
3325      SrcArgDRE->getDecl() != CompareWithSrcDRE->getDecl())
3326    return;
3327
3328  const Expr *OriginalSizeArg = Call->getArg(2);
3329  Diag(CompareWithSrcDRE->getLocStart(), diag::warn_strlcpycat_wrong_size)
3330    << OriginalSizeArg->getSourceRange() << FnName;
3331
3332  // Output a FIXIT hint if the destination is an array (rather than a
3333  // pointer to an array).  This could be enhanced to handle some
3334  // pointers if we know the actual size, like if DstArg is 'array+2'
3335  // we could say 'sizeof(array)-2'.
3336  const Expr *DstArg = Call->getArg(0)->IgnoreParenImpCasts();
3337  if (!isConstantSizeArrayWithMoreThanOneElement(DstArg->getType(), Context))
3338    return;
3339
3340  SmallString<128> sizeString;
3341  llvm::raw_svector_ostream OS(sizeString);
3342  OS << "sizeof(";
3343  DstArg->printPretty(OS, 0, getPrintingPolicy());
3344  OS << ")";
3345
3346  Diag(OriginalSizeArg->getLocStart(), diag::note_strlcpycat_wrong_size)
3347    << FixItHint::CreateReplacement(OriginalSizeArg->getSourceRange(),
3348                                    OS.str());
3349}
3350
3351/// Check if two expressions refer to the same declaration.
3352static bool referToTheSameDecl(const Expr *E1, const Expr *E2) {
3353  if (const DeclRefExpr *D1 = dyn_cast_or_null<DeclRefExpr>(E1))
3354    if (const DeclRefExpr *D2 = dyn_cast_or_null<DeclRefExpr>(E2))
3355      return D1->getDecl() == D2->getDecl();
3356  return false;
3357}
3358
3359static const Expr *getStrlenExprArg(const Expr *E) {
3360  if (const CallExpr *CE = dyn_cast<CallExpr>(E)) {
3361    const FunctionDecl *FD = CE->getDirectCallee();
3362    if (!FD || FD->getMemoryFunctionKind() != Builtin::BIstrlen)
3363      return 0;
3364    return CE->getArg(0)->IgnoreParenCasts();
3365  }
3366  return 0;
3367}
3368
3369// Warn on anti-patterns as the 'size' argument to strncat.
3370// The correct size argument should look like following:
3371//   strncat(dst, src, sizeof(dst) - strlen(dest) - 1);
3372void Sema::CheckStrncatArguments(const CallExpr *CE,
3373                                 IdentifierInfo *FnName) {
3374  // Don't crash if the user has the wrong number of arguments.
3375  if (CE->getNumArgs() < 3)
3376    return;
3377  const Expr *DstArg = CE->getArg(0)->IgnoreParenCasts();
3378  const Expr *SrcArg = CE->getArg(1)->IgnoreParenCasts();
3379  const Expr *LenArg = CE->getArg(2)->IgnoreParenCasts();
3380
3381  // Identify common expressions, which are wrongly used as the size argument
3382  // to strncat and may lead to buffer overflows.
3383  unsigned PatternType = 0;
3384  if (const Expr *SizeOfArg = getSizeOfExprArg(LenArg)) {
3385    // - sizeof(dst)
3386    if (referToTheSameDecl(SizeOfArg, DstArg))
3387      PatternType = 1;
3388    // - sizeof(src)
3389    else if (referToTheSameDecl(SizeOfArg, SrcArg))
3390      PatternType = 2;
3391  } else if (const BinaryOperator *BE = dyn_cast<BinaryOperator>(LenArg)) {
3392    if (BE->getOpcode() == BO_Sub) {
3393      const Expr *L = BE->getLHS()->IgnoreParenCasts();
3394      const Expr *R = BE->getRHS()->IgnoreParenCasts();
3395      // - sizeof(dst) - strlen(dst)
3396      if (referToTheSameDecl(DstArg, getSizeOfExprArg(L)) &&
3397          referToTheSameDecl(DstArg, getStrlenExprArg(R)))
3398        PatternType = 1;
3399      // - sizeof(src) - (anything)
3400      else if (referToTheSameDecl(SrcArg, getSizeOfExprArg(L)))
3401        PatternType = 2;
3402    }
3403  }
3404
3405  if (PatternType == 0)
3406    return;
3407
3408  // Generate the diagnostic.
3409  SourceLocation SL = LenArg->getLocStart();
3410  SourceRange SR = LenArg->getSourceRange();
3411  SourceManager &SM  = PP.getSourceManager();
3412
3413  // If the function is defined as a builtin macro, do not show macro expansion.
3414  if (SM.isMacroArgExpansion(SL)) {
3415    SL = SM.getSpellingLoc(SL);
3416    SR = SourceRange(SM.getSpellingLoc(SR.getBegin()),
3417                     SM.getSpellingLoc(SR.getEnd()));
3418  }
3419
3420  // Check if the destination is an array (rather than a pointer to an array).
3421  QualType DstTy = DstArg->getType();
3422  bool isKnownSizeArray = isConstantSizeArrayWithMoreThanOneElement(DstTy,
3423                                                                    Context);
3424  if (!isKnownSizeArray) {
3425    if (PatternType == 1)
3426      Diag(SL, diag::warn_strncat_wrong_size) << SR;
3427    else
3428      Diag(SL, diag::warn_strncat_src_size) << SR;
3429    return;
3430  }
3431
3432  if (PatternType == 1)
3433    Diag(SL, diag::warn_strncat_large_size) << SR;
3434  else
3435    Diag(SL, diag::warn_strncat_src_size) << SR;
3436
3437  SmallString<128> sizeString;
3438  llvm::raw_svector_ostream OS(sizeString);
3439  OS << "sizeof(";
3440  DstArg->printPretty(OS, 0, getPrintingPolicy());
3441  OS << ") - ";
3442  OS << "strlen(";
3443  DstArg->printPretty(OS, 0, getPrintingPolicy());
3444  OS << ") - 1";
3445
3446  Diag(SL, diag::note_strncat_wrong_size)
3447    << FixItHint::CreateReplacement(SR, OS.str());
3448}
3449
3450//===--- CHECK: Return Address of Stack Variable --------------------------===//
3451
3452static Expr *EvalVal(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars,
3453                     Decl *ParentDecl);
3454static Expr *EvalAddr(Expr* E, SmallVectorImpl<DeclRefExpr *> &refVars,
3455                      Decl *ParentDecl);
3456
3457/// CheckReturnStackAddr - Check if a return statement returns the address
3458///   of a stack variable.
3459void
3460Sema::CheckReturnStackAddr(Expr *RetValExp, QualType lhsType,
3461                           SourceLocation ReturnLoc) {
3462
3463  Expr *stackE = 0;
3464  SmallVector<DeclRefExpr *, 8> refVars;
3465
3466  // Perform checking for returned stack addresses, local blocks,
3467  // label addresses or references to temporaries.
3468  if (lhsType->isPointerType() ||
3469      (!getLangOpts().ObjCAutoRefCount && lhsType->isBlockPointerType())) {
3470    stackE = EvalAddr(RetValExp, refVars, /*ParentDecl=*/0);
3471  } else if (lhsType->isReferenceType()) {
3472    stackE = EvalVal(RetValExp, refVars, /*ParentDecl=*/0);
3473  }
3474
3475  if (stackE == 0)
3476    return; // Nothing suspicious was found.
3477
3478  SourceLocation diagLoc;
3479  SourceRange diagRange;
3480  if (refVars.empty()) {
3481    diagLoc = stackE->getLocStart();
3482    diagRange = stackE->getSourceRange();
3483  } else {
3484    // We followed through a reference variable. 'stackE' contains the
3485    // problematic expression but we will warn at the return statement pointing
3486    // at the reference variable. We will later display the "trail" of
3487    // reference variables using notes.
3488    diagLoc = refVars[0]->getLocStart();
3489    diagRange = refVars[0]->getSourceRange();
3490  }
3491
3492  if (DeclRefExpr *DR = dyn_cast<DeclRefExpr>(stackE)) { //address of local var.
3493    Diag(diagLoc, lhsType->isReferenceType() ? diag::warn_ret_stack_ref
3494                                             : diag::warn_ret_stack_addr)
3495     << DR->getDecl()->getDeclName() << diagRange;
3496  } else if (isa<BlockExpr>(stackE)) { // local block.
3497    Diag(diagLoc, diag::err_ret_local_block) << diagRange;
3498  } else if (isa<AddrLabelExpr>(stackE)) { // address of label.
3499    Diag(diagLoc, diag::warn_ret_addr_label) << diagRange;
3500  } else { // local temporary.
3501    Diag(diagLoc, lhsType->isReferenceType() ? diag::warn_ret_local_temp_ref
3502                                             : diag::warn_ret_local_temp_addr)
3503     << diagRange;
3504  }
3505
3506  // Display the "trail" of reference variables that we followed until we
3507  // found the problematic expression using notes.
3508  for (unsigned i = 0, e = refVars.size(); i != e; ++i) {
3509    VarDecl *VD = cast<VarDecl>(refVars[i]->getDecl());
3510    // If this var binds to another reference var, show the range of the next
3511    // var, otherwise the var binds to the problematic expression, in which case
3512    // show the range of the expression.
3513    SourceRange range = (i < e-1) ? refVars[i+1]->getSourceRange()
3514                                  : stackE->getSourceRange();
3515    Diag(VD->getLocation(), diag::note_ref_var_local_bind)
3516      << VD->getDeclName() << range;
3517  }
3518}
3519
3520/// EvalAddr - EvalAddr and EvalVal are mutually recursive functions that
3521///  check if the expression in a return statement evaluates to an address
3522///  to a location on the stack, a local block, an address of a label, or a
3523///  reference to local temporary. The recursion is used to traverse the
3524///  AST of the return expression, with recursion backtracking when we
3525///  encounter a subexpression that (1) clearly does not lead to one of the
3526///  above problematic expressions (2) is something we cannot determine leads to
3527///  a problematic expression based on such local checking.
3528///
3529///  Both EvalAddr and EvalVal follow through reference variables to evaluate
3530///  the expression that they point to. Such variables are added to the
3531///  'refVars' vector so that we know what the reference variable "trail" was.
3532///
3533///  EvalAddr processes expressions that are pointers that are used as
3534///  references (and not L-values).  EvalVal handles all other values.
3535///  At the base case of the recursion is a check for the above problematic
3536///  expressions.
3537///
3538///  This implementation handles:
3539///
3540///   * pointer-to-pointer casts
3541///   * implicit conversions from array references to pointers
3542///   * taking the address of fields
3543///   * arbitrary interplay between "&" and "*" operators
3544///   * pointer arithmetic from an address of a stack variable
3545///   * taking the address of an array element where the array is on the stack
3546static Expr *EvalAddr(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars,
3547                      Decl *ParentDecl) {
3548  if (E->isTypeDependent())
3549      return NULL;
3550
3551  // We should only be called for evaluating pointer expressions.
3552  assert((E->getType()->isAnyPointerType() ||
3553          E->getType()->isBlockPointerType() ||
3554          E->getType()->isObjCQualifiedIdType()) &&
3555         "EvalAddr only works on pointers");
3556
3557  E = E->IgnoreParens();
3558
3559  // Our "symbolic interpreter" is just a dispatch off the currently
3560  // viewed AST node.  We then recursively traverse the AST by calling
3561  // EvalAddr and EvalVal appropriately.
3562  switch (E->getStmtClass()) {
3563  case Stmt::DeclRefExprClass: {
3564    DeclRefExpr *DR = cast<DeclRefExpr>(E);
3565
3566    if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl()))
3567      // If this is a reference variable, follow through to the expression that
3568      // it points to.
3569      if (V->hasLocalStorage() &&
3570          V->getType()->isReferenceType() && V->hasInit()) {
3571        // Add the reference variable to the "trail".
3572        refVars.push_back(DR);
3573        return EvalAddr(V->getInit(), refVars, ParentDecl);
3574      }
3575
3576    return NULL;
3577  }
3578
3579  case Stmt::UnaryOperatorClass: {
3580    // The only unary operator that make sense to handle here
3581    // is AddrOf.  All others don't make sense as pointers.
3582    UnaryOperator *U = cast<UnaryOperator>(E);
3583
3584    if (U->getOpcode() == UO_AddrOf)
3585      return EvalVal(U->getSubExpr(), refVars, ParentDecl);
3586    else
3587      return NULL;
3588  }
3589
3590  case Stmt::BinaryOperatorClass: {
3591    // Handle pointer arithmetic.  All other binary operators are not valid
3592    // in this context.
3593    BinaryOperator *B = cast<BinaryOperator>(E);
3594    BinaryOperatorKind op = B->getOpcode();
3595
3596    if (op != BO_Add && op != BO_Sub)
3597      return NULL;
3598
3599    Expr *Base = B->getLHS();
3600
3601    // Determine which argument is the real pointer base.  It could be
3602    // the RHS argument instead of the LHS.
3603    if (!Base->getType()->isPointerType()) Base = B->getRHS();
3604
3605    assert (Base->getType()->isPointerType());
3606    return EvalAddr(Base, refVars, ParentDecl);
3607  }
3608
3609  // For conditional operators we need to see if either the LHS or RHS are
3610  // valid DeclRefExpr*s.  If one of them is valid, we return it.
3611  case Stmt::ConditionalOperatorClass: {
3612    ConditionalOperator *C = cast<ConditionalOperator>(E);
3613
3614    // Handle the GNU extension for missing LHS.
3615    if (Expr *lhsExpr = C->getLHS()) {
3616    // In C++, we can have a throw-expression, which has 'void' type.
3617      if (!lhsExpr->getType()->isVoidType())
3618        if (Expr* LHS = EvalAddr(lhsExpr, refVars, ParentDecl))
3619          return LHS;
3620    }
3621
3622    // In C++, we can have a throw-expression, which has 'void' type.
3623    if (C->getRHS()->getType()->isVoidType())
3624      return NULL;
3625
3626    return EvalAddr(C->getRHS(), refVars, ParentDecl);
3627  }
3628
3629  case Stmt::BlockExprClass:
3630    if (cast<BlockExpr>(E)->getBlockDecl()->hasCaptures())
3631      return E; // local block.
3632    return NULL;
3633
3634  case Stmt::AddrLabelExprClass:
3635    return E; // address of label.
3636
3637  case Stmt::ExprWithCleanupsClass:
3638    return EvalAddr(cast<ExprWithCleanups>(E)->getSubExpr(), refVars,
3639                    ParentDecl);
3640
3641  // For casts, we need to handle conversions from arrays to
3642  // pointer values, and pointer-to-pointer conversions.
3643  case Stmt::ImplicitCastExprClass:
3644  case Stmt::CStyleCastExprClass:
3645  case Stmt::CXXFunctionalCastExprClass:
3646  case Stmt::ObjCBridgedCastExprClass:
3647  case Stmt::CXXStaticCastExprClass:
3648  case Stmt::CXXDynamicCastExprClass:
3649  case Stmt::CXXConstCastExprClass:
3650  case Stmt::CXXReinterpretCastExprClass: {
3651    Expr* SubExpr = cast<CastExpr>(E)->getSubExpr();
3652    switch (cast<CastExpr>(E)->getCastKind()) {
3653    case CK_BitCast:
3654    case CK_LValueToRValue:
3655    case CK_NoOp:
3656    case CK_BaseToDerived:
3657    case CK_DerivedToBase:
3658    case CK_UncheckedDerivedToBase:
3659    case CK_Dynamic:
3660    case CK_CPointerToObjCPointerCast:
3661    case CK_BlockPointerToObjCPointerCast:
3662    case CK_AnyPointerToBlockPointerCast:
3663      return EvalAddr(SubExpr, refVars, ParentDecl);
3664
3665    case CK_ArrayToPointerDecay:
3666      return EvalVal(SubExpr, refVars, ParentDecl);
3667
3668    default:
3669      return 0;
3670    }
3671  }
3672
3673  case Stmt::MaterializeTemporaryExprClass:
3674    if (Expr *Result = EvalAddr(
3675                         cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(),
3676                                refVars, ParentDecl))
3677      return Result;
3678
3679    return E;
3680
3681  // Everything else: we simply don't reason about them.
3682  default:
3683    return NULL;
3684  }
3685}
3686
3687
3688///  EvalVal - This function is complements EvalAddr in the mutual recursion.
3689///   See the comments for EvalAddr for more details.
3690static Expr *EvalVal(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars,
3691                     Decl *ParentDecl) {
3692do {
3693  // We should only be called for evaluating non-pointer expressions, or
3694  // expressions with a pointer type that are not used as references but instead
3695  // are l-values (e.g., DeclRefExpr with a pointer type).
3696
3697  // Our "symbolic interpreter" is just a dispatch off the currently
3698  // viewed AST node.  We then recursively traverse the AST by calling
3699  // EvalAddr and EvalVal appropriately.
3700
3701  E = E->IgnoreParens();
3702  switch (E->getStmtClass()) {
3703  case Stmt::ImplicitCastExprClass: {
3704    ImplicitCastExpr *IE = cast<ImplicitCastExpr>(E);
3705    if (IE->getValueKind() == VK_LValue) {
3706      E = IE->getSubExpr();
3707      continue;
3708    }
3709    return NULL;
3710  }
3711
3712  case Stmt::ExprWithCleanupsClass:
3713    return EvalVal(cast<ExprWithCleanups>(E)->getSubExpr(), refVars,ParentDecl);
3714
3715  case Stmt::DeclRefExprClass: {
3716    // When we hit a DeclRefExpr we are looking at code that refers to a
3717    // variable's name. If it's not a reference variable we check if it has
3718    // local storage within the function, and if so, return the expression.
3719    DeclRefExpr *DR = cast<DeclRefExpr>(E);
3720
3721    if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl())) {
3722      // Check if it refers to itself, e.g. "int& i = i;".
3723      if (V == ParentDecl)
3724        return DR;
3725
3726      if (V->hasLocalStorage()) {
3727        if (!V->getType()->isReferenceType())
3728          return DR;
3729
3730        // Reference variable, follow through to the expression that
3731        // it points to.
3732        if (V->hasInit()) {
3733          // Add the reference variable to the "trail".
3734          refVars.push_back(DR);
3735          return EvalVal(V->getInit(), refVars, V);
3736        }
3737      }
3738    }
3739
3740    return NULL;
3741  }
3742
3743  case Stmt::UnaryOperatorClass: {
3744    // The only unary operator that make sense to handle here
3745    // is Deref.  All others don't resolve to a "name."  This includes
3746    // handling all sorts of rvalues passed to a unary operator.
3747    UnaryOperator *U = cast<UnaryOperator>(E);
3748
3749    if (U->getOpcode() == UO_Deref)
3750      return EvalAddr(U->getSubExpr(), refVars, ParentDecl);
3751
3752    return NULL;
3753  }
3754
3755  case Stmt::ArraySubscriptExprClass: {
3756    // Array subscripts are potential references to data on the stack.  We
3757    // retrieve the DeclRefExpr* for the array variable if it indeed
3758    // has local storage.
3759    return EvalAddr(cast<ArraySubscriptExpr>(E)->getBase(), refVars,ParentDecl);
3760  }
3761
3762  case Stmt::ConditionalOperatorClass: {
3763    // For conditional operators we need to see if either the LHS or RHS are
3764    // non-NULL Expr's.  If one is non-NULL, we return it.
3765    ConditionalOperator *C = cast<ConditionalOperator>(E);
3766
3767    // Handle the GNU extension for missing LHS.
3768    if (Expr *lhsExpr = C->getLHS())
3769      if (Expr *LHS = EvalVal(lhsExpr, refVars, ParentDecl))
3770        return LHS;
3771
3772    return EvalVal(C->getRHS(), refVars, ParentDecl);
3773  }
3774
3775  // Accesses to members are potential references to data on the stack.
3776  case Stmt::MemberExprClass: {
3777    MemberExpr *M = cast<MemberExpr>(E);
3778
3779    // Check for indirect access.  We only want direct field accesses.
3780    if (M->isArrow())
3781      return NULL;
3782
3783    // Check whether the member type is itself a reference, in which case
3784    // we're not going to refer to the member, but to what the member refers to.
3785    if (M->getMemberDecl()->getType()->isReferenceType())
3786      return NULL;
3787
3788    return EvalVal(M->getBase(), refVars, ParentDecl);
3789  }
3790
3791  case Stmt::MaterializeTemporaryExprClass:
3792    if (Expr *Result = EvalVal(
3793                          cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(),
3794                               refVars, ParentDecl))
3795      return Result;
3796
3797    return E;
3798
3799  default:
3800    // Check that we don't return or take the address of a reference to a
3801    // temporary. This is only useful in C++.
3802    if (!E->isTypeDependent() && E->isRValue())
3803      return E;
3804
3805    // Everything else: we simply don't reason about them.
3806    return NULL;
3807  }
3808} while (true);
3809}
3810
3811//===--- CHECK: Floating-Point comparisons (-Wfloat-equal) ---------------===//
3812
3813/// Check for comparisons of floating point operands using != and ==.
3814/// Issue a warning if these are no self-comparisons, as they are not likely
3815/// to do what the programmer intended.
3816void Sema::CheckFloatComparison(SourceLocation Loc, Expr* LHS, Expr *RHS) {
3817  Expr* LeftExprSansParen = LHS->IgnoreParenImpCasts();
3818  Expr* RightExprSansParen = RHS->IgnoreParenImpCasts();
3819
3820  // Special case: check for x == x (which is OK).
3821  // Do not emit warnings for such cases.
3822  if (DeclRefExpr* DRL = dyn_cast<DeclRefExpr>(LeftExprSansParen))
3823    if (DeclRefExpr* DRR = dyn_cast<DeclRefExpr>(RightExprSansParen))
3824      if (DRL->getDecl() == DRR->getDecl())
3825        return;
3826
3827
3828  // Special case: check for comparisons against literals that can be exactly
3829  //  represented by APFloat.  In such cases, do not emit a warning.  This
3830  //  is a heuristic: often comparison against such literals are used to
3831  //  detect if a value in a variable has not changed.  This clearly can
3832  //  lead to false negatives.
3833  if (FloatingLiteral* FLL = dyn_cast<FloatingLiteral>(LeftExprSansParen)) {
3834    if (FLL->isExact())
3835      return;
3836  } else
3837    if (FloatingLiteral* FLR = dyn_cast<FloatingLiteral>(RightExprSansParen))
3838      if (FLR->isExact())
3839        return;
3840
3841  // Check for comparisons with builtin types.
3842  if (CallExpr* CL = dyn_cast<CallExpr>(LeftExprSansParen))
3843    if (CL->isBuiltinCall())
3844      return;
3845
3846  if (CallExpr* CR = dyn_cast<CallExpr>(RightExprSansParen))
3847    if (CR->isBuiltinCall())
3848      return;
3849
3850  // Emit the diagnostic.
3851  Diag(Loc, diag::warn_floatingpoint_eq)
3852    << LHS->getSourceRange() << RHS->getSourceRange();
3853}
3854
3855//===--- CHECK: Integer mixed-sign comparisons (-Wsign-compare) --------===//
3856//===--- CHECK: Lossy implicit conversions (-Wconversion) --------------===//
3857
3858namespace {
3859
3860/// Structure recording the 'active' range of an integer-valued
3861/// expression.
3862struct IntRange {
3863  /// The number of bits active in the int.
3864  unsigned Width;
3865
3866  /// True if the int is known not to have negative values.
3867  bool NonNegative;
3868
3869  IntRange(unsigned Width, bool NonNegative)
3870    : Width(Width), NonNegative(NonNegative)
3871  {}
3872
3873  /// Returns the range of the bool type.
3874  static IntRange forBoolType() {
3875    return IntRange(1, true);
3876  }
3877
3878  /// Returns the range of an opaque value of the given integral type.
3879  static IntRange forValueOfType(ASTContext &C, QualType T) {
3880    return forValueOfCanonicalType(C,
3881                          T->getCanonicalTypeInternal().getTypePtr());
3882  }
3883
3884  /// Returns the range of an opaque value of a canonical integral type.
3885  static IntRange forValueOfCanonicalType(ASTContext &C, const Type *T) {
3886    assert(T->isCanonicalUnqualified());
3887
3888    if (const VectorType *VT = dyn_cast<VectorType>(T))
3889      T = VT->getElementType().getTypePtr();
3890    if (const ComplexType *CT = dyn_cast<ComplexType>(T))
3891      T = CT->getElementType().getTypePtr();
3892
3893    // For enum types, use the known bit width of the enumerators.
3894    if (const EnumType *ET = dyn_cast<EnumType>(T)) {
3895      EnumDecl *Enum = ET->getDecl();
3896      if (!Enum->isCompleteDefinition())
3897        return IntRange(C.getIntWidth(QualType(T, 0)), false);
3898
3899      unsigned NumPositive = Enum->getNumPositiveBits();
3900      unsigned NumNegative = Enum->getNumNegativeBits();
3901
3902      return IntRange(std::max(NumPositive, NumNegative), NumNegative == 0);
3903    }
3904
3905    const BuiltinType *BT = cast<BuiltinType>(T);
3906    assert(BT->isInteger());
3907
3908    return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger());
3909  }
3910
3911  /// Returns the "target" range of a canonical integral type, i.e.
3912  /// the range of values expressible in the type.
3913  ///
3914  /// This matches forValueOfCanonicalType except that enums have the
3915  /// full range of their type, not the range of their enumerators.
3916  static IntRange forTargetOfCanonicalType(ASTContext &C, const Type *T) {
3917    assert(T->isCanonicalUnqualified());
3918
3919    if (const VectorType *VT = dyn_cast<VectorType>(T))
3920      T = VT->getElementType().getTypePtr();
3921    if (const ComplexType *CT = dyn_cast<ComplexType>(T))
3922      T = CT->getElementType().getTypePtr();
3923    if (const EnumType *ET = dyn_cast<EnumType>(T))
3924      T = C.getCanonicalType(ET->getDecl()->getIntegerType()).getTypePtr();
3925
3926    const BuiltinType *BT = cast<BuiltinType>(T);
3927    assert(BT->isInteger());
3928
3929    return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger());
3930  }
3931
3932  /// Returns the supremum of two ranges: i.e. their conservative merge.
3933  static IntRange join(IntRange L, IntRange R) {
3934    return IntRange(std::max(L.Width, R.Width),
3935                    L.NonNegative && R.NonNegative);
3936  }
3937
3938  /// Returns the infinum of two ranges: i.e. their aggressive merge.
3939  static IntRange meet(IntRange L, IntRange R) {
3940    return IntRange(std::min(L.Width, R.Width),
3941                    L.NonNegative || R.NonNegative);
3942  }
3943};
3944
3945static IntRange GetValueRange(ASTContext &C, llvm::APSInt &value,
3946                              unsigned MaxWidth) {
3947  if (value.isSigned() && value.isNegative())
3948    return IntRange(value.getMinSignedBits(), false);
3949
3950  if (value.getBitWidth() > MaxWidth)
3951    value = value.trunc(MaxWidth);
3952
3953  // isNonNegative() just checks the sign bit without considering
3954  // signedness.
3955  return IntRange(value.getActiveBits(), true);
3956}
3957
3958static IntRange GetValueRange(ASTContext &C, APValue &result, QualType Ty,
3959                              unsigned MaxWidth) {
3960  if (result.isInt())
3961    return GetValueRange(C, result.getInt(), MaxWidth);
3962
3963  if (result.isVector()) {
3964    IntRange R = GetValueRange(C, result.getVectorElt(0), Ty, MaxWidth);
3965    for (unsigned i = 1, e = result.getVectorLength(); i != e; ++i) {
3966      IntRange El = GetValueRange(C, result.getVectorElt(i), Ty, MaxWidth);
3967      R = IntRange::join(R, El);
3968    }
3969    return R;
3970  }
3971
3972  if (result.isComplexInt()) {
3973    IntRange R = GetValueRange(C, result.getComplexIntReal(), MaxWidth);
3974    IntRange I = GetValueRange(C, result.getComplexIntImag(), MaxWidth);
3975    return IntRange::join(R, I);
3976  }
3977
3978  // This can happen with lossless casts to intptr_t of "based" lvalues.
3979  // Assume it might use arbitrary bits.
3980  // FIXME: The only reason we need to pass the type in here is to get
3981  // the sign right on this one case.  It would be nice if APValue
3982  // preserved this.
3983  assert(result.isLValue() || result.isAddrLabelDiff());
3984  return IntRange(MaxWidth, Ty->isUnsignedIntegerOrEnumerationType());
3985}
3986
3987/// Pseudo-evaluate the given integer expression, estimating the
3988/// range of values it might take.
3989///
3990/// \param MaxWidth - the width to which the value will be truncated
3991static IntRange GetExprRange(ASTContext &C, Expr *E, unsigned MaxWidth) {
3992  E = E->IgnoreParens();
3993
3994  // Try a full evaluation first.
3995  Expr::EvalResult result;
3996  if (E->EvaluateAsRValue(result, C))
3997    return GetValueRange(C, result.Val, E->getType(), MaxWidth);
3998
3999  // I think we only want to look through implicit casts here; if the
4000  // user has an explicit widening cast, we should treat the value as
4001  // being of the new, wider type.
4002  if (ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E)) {
4003    if (CE->getCastKind() == CK_NoOp || CE->getCastKind() == CK_LValueToRValue)
4004      return GetExprRange(C, CE->getSubExpr(), MaxWidth);
4005
4006    IntRange OutputTypeRange = IntRange::forValueOfType(C, CE->getType());
4007
4008    bool isIntegerCast = (CE->getCastKind() == CK_IntegralCast);
4009
4010    // Assume that non-integer casts can span the full range of the type.
4011    if (!isIntegerCast)
4012      return OutputTypeRange;
4013
4014    IntRange SubRange
4015      = GetExprRange(C, CE->getSubExpr(),
4016                     std::min(MaxWidth, OutputTypeRange.Width));
4017
4018    // Bail out if the subexpr's range is as wide as the cast type.
4019    if (SubRange.Width >= OutputTypeRange.Width)
4020      return OutputTypeRange;
4021
4022    // Otherwise, we take the smaller width, and we're non-negative if
4023    // either the output type or the subexpr is.
4024    return IntRange(SubRange.Width,
4025                    SubRange.NonNegative || OutputTypeRange.NonNegative);
4026  }
4027
4028  if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) {
4029    // If we can fold the condition, just take that operand.
4030    bool CondResult;
4031    if (CO->getCond()->EvaluateAsBooleanCondition(CondResult, C))
4032      return GetExprRange(C, CondResult ? CO->getTrueExpr()
4033                                        : CO->getFalseExpr(),
4034                          MaxWidth);
4035
4036    // Otherwise, conservatively merge.
4037    IntRange L = GetExprRange(C, CO->getTrueExpr(), MaxWidth);
4038    IntRange R = GetExprRange(C, CO->getFalseExpr(), MaxWidth);
4039    return IntRange::join(L, R);
4040  }
4041
4042  if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {
4043    switch (BO->getOpcode()) {
4044
4045    // Boolean-valued operations are single-bit and positive.
4046    case BO_LAnd:
4047    case BO_LOr:
4048    case BO_LT:
4049    case BO_GT:
4050    case BO_LE:
4051    case BO_GE:
4052    case BO_EQ:
4053    case BO_NE:
4054      return IntRange::forBoolType();
4055
4056    // The type of the assignments is the type of the LHS, so the RHS
4057    // is not necessarily the same type.
4058    case BO_MulAssign:
4059    case BO_DivAssign:
4060    case BO_RemAssign:
4061    case BO_AddAssign:
4062    case BO_SubAssign:
4063    case BO_XorAssign:
4064    case BO_OrAssign:
4065      // TODO: bitfields?
4066      return IntRange::forValueOfType(C, E->getType());
4067
4068    // Simple assignments just pass through the RHS, which will have
4069    // been coerced to the LHS type.
4070    case BO_Assign:
4071      // TODO: bitfields?
4072      return GetExprRange(C, BO->getRHS(), MaxWidth);
4073
4074    // Operations with opaque sources are black-listed.
4075    case BO_PtrMemD:
4076    case BO_PtrMemI:
4077      return IntRange::forValueOfType(C, E->getType());
4078
4079    // Bitwise-and uses the *infinum* of the two source ranges.
4080    case BO_And:
4081    case BO_AndAssign:
4082      return IntRange::meet(GetExprRange(C, BO->getLHS(), MaxWidth),
4083                            GetExprRange(C, BO->getRHS(), MaxWidth));
4084
4085    // Left shift gets black-listed based on a judgement call.
4086    case BO_Shl:
4087      // ...except that we want to treat '1 << (blah)' as logically
4088      // positive.  It's an important idiom.
4089      if (IntegerLiteral *I
4090            = dyn_cast<IntegerLiteral>(BO->getLHS()->IgnoreParenCasts())) {
4091        if (I->getValue() == 1) {
4092          IntRange R = IntRange::forValueOfType(C, E->getType());
4093          return IntRange(R.Width, /*NonNegative*/ true);
4094        }
4095      }
4096      // fallthrough
4097
4098    case BO_ShlAssign:
4099      return IntRange::forValueOfType(C, E->getType());
4100
4101    // Right shift by a constant can narrow its left argument.
4102    case BO_Shr:
4103    case BO_ShrAssign: {
4104      IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth);
4105
4106      // If the shift amount is a positive constant, drop the width by
4107      // that much.
4108      llvm::APSInt shift;
4109      if (BO->getRHS()->isIntegerConstantExpr(shift, C) &&
4110          shift.isNonNegative()) {
4111        unsigned zext = shift.getZExtValue();
4112        if (zext >= L.Width)
4113          L.Width = (L.NonNegative ? 0 : 1);
4114        else
4115          L.Width -= zext;
4116      }
4117
4118      return L;
4119    }
4120
4121    // Comma acts as its right operand.
4122    case BO_Comma:
4123      return GetExprRange(C, BO->getRHS(), MaxWidth);
4124
4125    // Black-list pointer subtractions.
4126    case BO_Sub:
4127      if (BO->getLHS()->getType()->isPointerType())
4128        return IntRange::forValueOfType(C, E->getType());
4129      break;
4130
4131    // The width of a division result is mostly determined by the size
4132    // of the LHS.
4133    case BO_Div: {
4134      // Don't 'pre-truncate' the operands.
4135      unsigned opWidth = C.getIntWidth(E->getType());
4136      IntRange L = GetExprRange(C, BO->getLHS(), opWidth);
4137
4138      // If the divisor is constant, use that.
4139      llvm::APSInt divisor;
4140      if (BO->getRHS()->isIntegerConstantExpr(divisor, C)) {
4141        unsigned log2 = divisor.logBase2(); // floor(log_2(divisor))
4142        if (log2 >= L.Width)
4143          L.Width = (L.NonNegative ? 0 : 1);
4144        else
4145          L.Width = std::min(L.Width - log2, MaxWidth);
4146        return L;
4147      }
4148
4149      // Otherwise, just use the LHS's width.
4150      IntRange R = GetExprRange(C, BO->getRHS(), opWidth);
4151      return IntRange(L.Width, L.NonNegative && R.NonNegative);
4152    }
4153
4154    // The result of a remainder can't be larger than the result of
4155    // either side.
4156    case BO_Rem: {
4157      // Don't 'pre-truncate' the operands.
4158      unsigned opWidth = C.getIntWidth(E->getType());
4159      IntRange L = GetExprRange(C, BO->getLHS(), opWidth);
4160      IntRange R = GetExprRange(C, BO->getRHS(), opWidth);
4161
4162      IntRange meet = IntRange::meet(L, R);
4163      meet.Width = std::min(meet.Width, MaxWidth);
4164      return meet;
4165    }
4166
4167    // The default behavior is okay for these.
4168    case BO_Mul:
4169    case BO_Add:
4170    case BO_Xor:
4171    case BO_Or:
4172      break;
4173    }
4174
4175    // The default case is to treat the operation as if it were closed
4176    // on the narrowest type that encompasses both operands.
4177    IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth);
4178    IntRange R = GetExprRange(C, BO->getRHS(), MaxWidth);
4179    return IntRange::join(L, R);
4180  }
4181
4182  if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) {
4183    switch (UO->getOpcode()) {
4184    // Boolean-valued operations are white-listed.
4185    case UO_LNot:
4186      return IntRange::forBoolType();
4187
4188    // Operations with opaque sources are black-listed.
4189    case UO_Deref:
4190    case UO_AddrOf: // should be impossible
4191      return IntRange::forValueOfType(C, E->getType());
4192
4193    default:
4194      return GetExprRange(C, UO->getSubExpr(), MaxWidth);
4195    }
4196  }
4197
4198  if (dyn_cast<OffsetOfExpr>(E)) {
4199    IntRange::forValueOfType(C, E->getType());
4200  }
4201
4202  if (FieldDecl *BitField = E->getBitField())
4203    return IntRange(BitField->getBitWidthValue(C),
4204                    BitField->getType()->isUnsignedIntegerOrEnumerationType());
4205
4206  return IntRange::forValueOfType(C, E->getType());
4207}
4208
4209static IntRange GetExprRange(ASTContext &C, Expr *E) {
4210  return GetExprRange(C, E, C.getIntWidth(E->getType()));
4211}
4212
4213/// Checks whether the given value, which currently has the given
4214/// source semantics, has the same value when coerced through the
4215/// target semantics.
4216static bool IsSameFloatAfterCast(const llvm::APFloat &value,
4217                                 const llvm::fltSemantics &Src,
4218                                 const llvm::fltSemantics &Tgt) {
4219  llvm::APFloat truncated = value;
4220
4221  bool ignored;
4222  truncated.convert(Src, llvm::APFloat::rmNearestTiesToEven, &ignored);
4223  truncated.convert(Tgt, llvm::APFloat::rmNearestTiesToEven, &ignored);
4224
4225  return truncated.bitwiseIsEqual(value);
4226}
4227
4228/// Checks whether the given value, which currently has the given
4229/// source semantics, has the same value when coerced through the
4230/// target semantics.
4231///
4232/// The value might be a vector of floats (or a complex number).
4233static bool IsSameFloatAfterCast(const APValue &value,
4234                                 const llvm::fltSemantics &Src,
4235                                 const llvm::fltSemantics &Tgt) {
4236  if (value.isFloat())
4237    return IsSameFloatAfterCast(value.getFloat(), Src, Tgt);
4238
4239  if (value.isVector()) {
4240    for (unsigned i = 0, e = value.getVectorLength(); i != e; ++i)
4241      if (!IsSameFloatAfterCast(value.getVectorElt(i), Src, Tgt))
4242        return false;
4243    return true;
4244  }
4245
4246  assert(value.isComplexFloat());
4247  return (IsSameFloatAfterCast(value.getComplexFloatReal(), Src, Tgt) &&
4248          IsSameFloatAfterCast(value.getComplexFloatImag(), Src, Tgt));
4249}
4250
4251static void AnalyzeImplicitConversions(Sema &S, Expr *E, SourceLocation CC);
4252
4253static bool IsZero(Sema &S, Expr *E) {
4254  // Suppress cases where we are comparing against an enum constant.
4255  if (const DeclRefExpr *DR =
4256      dyn_cast<DeclRefExpr>(E->IgnoreParenImpCasts()))
4257    if (isa<EnumConstantDecl>(DR->getDecl()))
4258      return false;
4259
4260  // Suppress cases where the '0' value is expanded from a macro.
4261  if (E->getLocStart().isMacroID())
4262    return false;
4263
4264  llvm::APSInt Value;
4265  return E->isIntegerConstantExpr(Value, S.Context) && Value == 0;
4266}
4267
4268static bool HasEnumType(Expr *E) {
4269  // Strip off implicit integral promotions.
4270  while (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) {
4271    if (ICE->getCastKind() != CK_IntegralCast &&
4272        ICE->getCastKind() != CK_NoOp)
4273      break;
4274    E = ICE->getSubExpr();
4275  }
4276
4277  return E->getType()->isEnumeralType();
4278}
4279
4280static void CheckTrivialUnsignedComparison(Sema &S, BinaryOperator *E) {
4281  BinaryOperatorKind op = E->getOpcode();
4282  if (E->isValueDependent())
4283    return;
4284
4285  if (op == BO_LT && IsZero(S, E->getRHS())) {
4286    S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison)
4287      << "< 0" << "false" << HasEnumType(E->getLHS())
4288      << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
4289  } else if (op == BO_GE && IsZero(S, E->getRHS())) {
4290    S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison)
4291      << ">= 0" << "true" << HasEnumType(E->getLHS())
4292      << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
4293  } else if (op == BO_GT && IsZero(S, E->getLHS())) {
4294    S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison)
4295      << "0 >" << "false" << HasEnumType(E->getRHS())
4296      << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
4297  } else if (op == BO_LE && IsZero(S, E->getLHS())) {
4298    S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison)
4299      << "0 <=" << "true" << HasEnumType(E->getRHS())
4300      << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
4301  }
4302}
4303
4304static void DiagnoseOutOfRangeComparison(Sema &S, BinaryOperator *E,
4305                                         Expr *lit, Expr *other,
4306                                         llvm::APSInt Value,
4307                                         bool rhsLiteral) {
4308  BinaryOperatorKind op = E->getOpcode();
4309  QualType OtherT = other->getType();
4310  const Type *OtherPtrT = S.Context.getCanonicalType(OtherT).getTypePtr();
4311  const Type *LitPtrT = S.Context.getCanonicalType(lit->getType()).getTypePtr();
4312  if (OtherPtrT == LitPtrT)
4313    return;
4314  assert((OtherT->isIntegerType() && LitPtrT->isIntegerType())
4315         && "comparison with non-integer type");
4316  IntRange OtherRange = IntRange::forValueOfType(S.Context, OtherT);
4317  IntRange LitRange = GetExprRange(S.Context, lit);
4318  if (OtherRange.Width >= LitRange.Width)
4319    return;
4320  std::string PrettySourceValue = Value.toString(10);
4321  bool IsTrue = true;
4322  if (op == BO_EQ)
4323    IsTrue = false;
4324  else if (op == BO_NE)
4325    IsTrue = true;
4326  else if (rhsLiteral) {
4327    if (op == BO_GT || op == BO_GE)
4328      IsTrue = !LitRange.NonNegative;
4329    else // op == BO_LT || op == BO_LE
4330      IsTrue = LitRange.NonNegative;
4331  }
4332  else {
4333    if (op == BO_LT || op == BO_LE)
4334      IsTrue = !LitRange.NonNegative;
4335    else // op == BO_GT || op == BO_GE
4336      IsTrue = LitRange.NonNegative;
4337  }
4338  S.Diag(E->getOperatorLoc(), diag::warn_outof_range_compare)
4339  << PrettySourceValue << other->getType() << IsTrue
4340  << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
4341}
4342
4343/// Analyze the operands of the given comparison.  Implements the
4344/// fallback case from AnalyzeComparison.
4345static void AnalyzeImpConvsInComparison(Sema &S, BinaryOperator *E) {
4346  AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc());
4347  AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc());
4348}
4349
4350/// \brief Implements -Wsign-compare.
4351///
4352/// \param E the binary operator to check for warnings
4353static void AnalyzeComparison(Sema &S, BinaryOperator *E) {
4354  // The type the comparison is being performed in.
4355  QualType T = E->getLHS()->getType();
4356  assert(S.Context.hasSameUnqualifiedType(T, E->getRHS()->getType())
4357         && "comparison with mismatched types");
4358  if (E->isValueDependent())
4359    return AnalyzeImpConvsInComparison(S, E);
4360
4361  Expr *LHS = E->getLHS()->IgnoreParenImpCasts();
4362  Expr *RHS = E->getRHS()->IgnoreParenImpCasts();
4363
4364  bool IsComparisonConstant = false;
4365
4366  // Check that an integer constant comparison results in a value
4367  // of 'true' or 'false'.
4368  if (T->isIntegralType(S.Context)) {
4369    llvm::APSInt RHSValue;
4370    bool IsRHSIntegralLiteral =
4371      RHS->isIntegerConstantExpr(RHSValue, S.Context);
4372    llvm::APSInt LHSValue;
4373    bool IsLHSIntegralLiteral =
4374      LHS->isIntegerConstantExpr(LHSValue, S.Context);
4375    if (IsRHSIntegralLiteral && !IsLHSIntegralLiteral)
4376        DiagnoseOutOfRangeComparison(S, E, RHS, LHS, RHSValue, true);
4377    else if (!IsRHSIntegralLiteral && IsLHSIntegralLiteral)
4378      DiagnoseOutOfRangeComparison(S, E, LHS, RHS, LHSValue, false);
4379    else
4380      IsComparisonConstant =
4381        (IsRHSIntegralLiteral && IsLHSIntegralLiteral);
4382  }
4383  else if (!T->hasUnsignedIntegerRepresentation())
4384    IsComparisonConstant = E->isIntegerConstantExpr(S.Context);
4385
4386  // We don't do anything special if this isn't an unsigned integral
4387  // comparison:  we're only interested in integral comparisons, and
4388  // signed comparisons only happen in cases we don't care to warn about.
4389  //
4390  // We also don't care about value-dependent expressions or expressions
4391  // whose result is a constant.
4392  if (!T->hasUnsignedIntegerRepresentation() || IsComparisonConstant)
4393    return AnalyzeImpConvsInComparison(S, E);
4394
4395  // Check to see if one of the (unmodified) operands is of different
4396  // signedness.
4397  Expr *signedOperand, *unsignedOperand;
4398  if (LHS->getType()->hasSignedIntegerRepresentation()) {
4399    assert(!RHS->getType()->hasSignedIntegerRepresentation() &&
4400           "unsigned comparison between two signed integer expressions?");
4401    signedOperand = LHS;
4402    unsignedOperand = RHS;
4403  } else if (RHS->getType()->hasSignedIntegerRepresentation()) {
4404    signedOperand = RHS;
4405    unsignedOperand = LHS;
4406  } else {
4407    CheckTrivialUnsignedComparison(S, E);
4408    return AnalyzeImpConvsInComparison(S, E);
4409  }
4410
4411  // Otherwise, calculate the effective range of the signed operand.
4412  IntRange signedRange = GetExprRange(S.Context, signedOperand);
4413
4414  // Go ahead and analyze implicit conversions in the operands.  Note
4415  // that we skip the implicit conversions on both sides.
4416  AnalyzeImplicitConversions(S, LHS, E->getOperatorLoc());
4417  AnalyzeImplicitConversions(S, RHS, E->getOperatorLoc());
4418
4419  // If the signed range is non-negative, -Wsign-compare won't fire,
4420  // but we should still check for comparisons which are always true
4421  // or false.
4422  if (signedRange.NonNegative)
4423    return CheckTrivialUnsignedComparison(S, E);
4424
4425  // For (in)equality comparisons, if the unsigned operand is a
4426  // constant which cannot collide with a overflowed signed operand,
4427  // then reinterpreting the signed operand as unsigned will not
4428  // change the result of the comparison.
4429  if (E->isEqualityOp()) {
4430    unsigned comparisonWidth = S.Context.getIntWidth(T);
4431    IntRange unsignedRange = GetExprRange(S.Context, unsignedOperand);
4432
4433    // We should never be unable to prove that the unsigned operand is
4434    // non-negative.
4435    assert(unsignedRange.NonNegative && "unsigned range includes negative?");
4436
4437    if (unsignedRange.Width < comparisonWidth)
4438      return;
4439  }
4440
4441  S.DiagRuntimeBehavior(E->getOperatorLoc(), E,
4442    S.PDiag(diag::warn_mixed_sign_comparison)
4443      << LHS->getType() << RHS->getType()
4444      << LHS->getSourceRange() << RHS->getSourceRange());
4445}
4446
4447/// Analyzes an attempt to assign the given value to a bitfield.
4448///
4449/// Returns true if there was something fishy about the attempt.
4450static bool AnalyzeBitFieldAssignment(Sema &S, FieldDecl *Bitfield, Expr *Init,
4451                                      SourceLocation InitLoc) {
4452  assert(Bitfield->isBitField());
4453  if (Bitfield->isInvalidDecl())
4454    return false;
4455
4456  // White-list bool bitfields.
4457  if (Bitfield->getType()->isBooleanType())
4458    return false;
4459
4460  // Ignore value- or type-dependent expressions.
4461  if (Bitfield->getBitWidth()->isValueDependent() ||
4462      Bitfield->getBitWidth()->isTypeDependent() ||
4463      Init->isValueDependent() ||
4464      Init->isTypeDependent())
4465    return false;
4466
4467  Expr *OriginalInit = Init->IgnoreParenImpCasts();
4468
4469  llvm::APSInt Value;
4470  if (!OriginalInit->EvaluateAsInt(Value, S.Context, Expr::SE_AllowSideEffects))
4471    return false;
4472
4473  unsigned OriginalWidth = Value.getBitWidth();
4474  unsigned FieldWidth = Bitfield->getBitWidthValue(S.Context);
4475
4476  if (OriginalWidth <= FieldWidth)
4477    return false;
4478
4479  // Compute the value which the bitfield will contain.
4480  llvm::APSInt TruncatedValue = Value.trunc(FieldWidth);
4481  TruncatedValue.setIsSigned(Bitfield->getType()->isSignedIntegerType());
4482
4483  // Check whether the stored value is equal to the original value.
4484  TruncatedValue = TruncatedValue.extend(OriginalWidth);
4485  if (llvm::APSInt::isSameValue(Value, TruncatedValue))
4486    return false;
4487
4488  // Special-case bitfields of width 1: booleans are naturally 0/1, and
4489  // therefore don't strictly fit into a signed bitfield of width 1.
4490  if (FieldWidth == 1 && Value == 1)
4491    return false;
4492
4493  std::string PrettyValue = Value.toString(10);
4494  std::string PrettyTrunc = TruncatedValue.toString(10);
4495
4496  S.Diag(InitLoc, diag::warn_impcast_bitfield_precision_constant)
4497    << PrettyValue << PrettyTrunc << OriginalInit->getType()
4498    << Init->getSourceRange();
4499
4500  return true;
4501}
4502
4503/// Analyze the given simple or compound assignment for warning-worthy
4504/// operations.
4505static void AnalyzeAssignment(Sema &S, BinaryOperator *E) {
4506  // Just recurse on the LHS.
4507  AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc());
4508
4509  // We want to recurse on the RHS as normal unless we're assigning to
4510  // a bitfield.
4511  if (FieldDecl *Bitfield = E->getLHS()->getBitField()) {
4512    if (AnalyzeBitFieldAssignment(S, Bitfield, E->getRHS(),
4513                                  E->getOperatorLoc())) {
4514      // Recurse, ignoring any implicit conversions on the RHS.
4515      return AnalyzeImplicitConversions(S, E->getRHS()->IgnoreParenImpCasts(),
4516                                        E->getOperatorLoc());
4517    }
4518  }
4519
4520  AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc());
4521}
4522
4523/// Diagnose an implicit cast;  purely a helper for CheckImplicitConversion.
4524static void DiagnoseImpCast(Sema &S, Expr *E, QualType SourceType, QualType T,
4525                            SourceLocation CContext, unsigned diag,
4526                            bool pruneControlFlow = false) {
4527  if (pruneControlFlow) {
4528    S.DiagRuntimeBehavior(E->getExprLoc(), E,
4529                          S.PDiag(diag)
4530                            << SourceType << T << E->getSourceRange()
4531                            << SourceRange(CContext));
4532    return;
4533  }
4534  S.Diag(E->getExprLoc(), diag)
4535    << SourceType << T << E->getSourceRange() << SourceRange(CContext);
4536}
4537
4538/// Diagnose an implicit cast;  purely a helper for CheckImplicitConversion.
4539static void DiagnoseImpCast(Sema &S, Expr *E, QualType T,
4540                            SourceLocation CContext, unsigned diag,
4541                            bool pruneControlFlow = false) {
4542  DiagnoseImpCast(S, E, E->getType(), T, CContext, diag, pruneControlFlow);
4543}
4544
4545/// Diagnose an implicit cast from a literal expression. Does not warn when the
4546/// cast wouldn't lose information.
4547void DiagnoseFloatingLiteralImpCast(Sema &S, FloatingLiteral *FL, QualType T,
4548                                    SourceLocation CContext) {
4549  // Try to convert the literal exactly to an integer. If we can, don't warn.
4550  bool isExact = false;
4551  const llvm::APFloat &Value = FL->getValue();
4552  llvm::APSInt IntegerValue(S.Context.getIntWidth(T),
4553                            T->hasUnsignedIntegerRepresentation());
4554  if (Value.convertToInteger(IntegerValue,
4555                             llvm::APFloat::rmTowardZero, &isExact)
4556      == llvm::APFloat::opOK && isExact)
4557    return;
4558
4559  SmallString<16> PrettySourceValue;
4560  Value.toString(PrettySourceValue);
4561  SmallString<16> PrettyTargetValue;
4562  if (T->isSpecificBuiltinType(BuiltinType::Bool))
4563    PrettyTargetValue = IntegerValue == 0 ? "false" : "true";
4564  else
4565    IntegerValue.toString(PrettyTargetValue);
4566
4567  S.Diag(FL->getExprLoc(), diag::warn_impcast_literal_float_to_integer)
4568    << FL->getType() << T.getUnqualifiedType() << PrettySourceValue
4569    << PrettyTargetValue << FL->getSourceRange() << SourceRange(CContext);
4570}
4571
4572std::string PrettyPrintInRange(const llvm::APSInt &Value, IntRange Range) {
4573  if (!Range.Width) return "0";
4574
4575  llvm::APSInt ValueInRange = Value;
4576  ValueInRange.setIsSigned(!Range.NonNegative);
4577  ValueInRange = ValueInRange.trunc(Range.Width);
4578  return ValueInRange.toString(10);
4579}
4580
4581static bool IsImplicitBoolFloatConversion(Sema &S, Expr *Ex, bool ToBool) {
4582  if (!isa<ImplicitCastExpr>(Ex))
4583    return false;
4584
4585  Expr *InnerE = Ex->IgnoreParenImpCasts();
4586  const Type *Target = S.Context.getCanonicalType(Ex->getType()).getTypePtr();
4587  const Type *Source =
4588    S.Context.getCanonicalType(InnerE->getType()).getTypePtr();
4589  if (Target->isDependentType())
4590    return false;
4591
4592  const BuiltinType *FloatCandidateBT =
4593    dyn_cast<BuiltinType>(ToBool ? Source : Target);
4594  const Type *BoolCandidateType = ToBool ? Target : Source;
4595
4596  return (BoolCandidateType->isSpecificBuiltinType(BuiltinType::Bool) &&
4597          FloatCandidateBT && (FloatCandidateBT->isFloatingPoint()));
4598}
4599
4600void CheckImplicitArgumentConversions(Sema &S, CallExpr *TheCall,
4601                                      SourceLocation CC) {
4602  unsigned NumArgs = TheCall->getNumArgs();
4603  for (unsigned i = 0; i < NumArgs; ++i) {
4604    Expr *CurrA = TheCall->getArg(i);
4605    if (!IsImplicitBoolFloatConversion(S, CurrA, true))
4606      continue;
4607
4608    bool IsSwapped = ((i > 0) &&
4609        IsImplicitBoolFloatConversion(S, TheCall->getArg(i - 1), false));
4610    IsSwapped |= ((i < (NumArgs - 1)) &&
4611        IsImplicitBoolFloatConversion(S, TheCall->getArg(i + 1), false));
4612    if (IsSwapped) {
4613      // Warn on this floating-point to bool conversion.
4614      DiagnoseImpCast(S, CurrA->IgnoreParenImpCasts(),
4615                      CurrA->getType(), CC,
4616                      diag::warn_impcast_floating_point_to_bool);
4617    }
4618  }
4619}
4620
4621void CheckImplicitConversion(Sema &S, Expr *E, QualType T,
4622                             SourceLocation CC, bool *ICContext = 0) {
4623  if (E->isTypeDependent() || E->isValueDependent()) return;
4624
4625  const Type *Source = S.Context.getCanonicalType(E->getType()).getTypePtr();
4626  const Type *Target = S.Context.getCanonicalType(T).getTypePtr();
4627  if (Source == Target) return;
4628  if (Target->isDependentType()) return;
4629
4630  // If the conversion context location is invalid don't complain. We also
4631  // don't want to emit a warning if the issue occurs from the expansion of
4632  // a system macro. The problem is that 'getSpellingLoc()' is slow, so we
4633  // delay this check as long as possible. Once we detect we are in that
4634  // scenario, we just return.
4635  if (CC.isInvalid())
4636    return;
4637
4638  // Diagnose implicit casts to bool.
4639  if (Target->isSpecificBuiltinType(BuiltinType::Bool)) {
4640    if (isa<StringLiteral>(E))
4641      // Warn on string literal to bool.  Checks for string literals in logical
4642      // expressions, for instances, assert(0 && "error here"), is prevented
4643      // by a check in AnalyzeImplicitConversions().
4644      return DiagnoseImpCast(S, E, T, CC,
4645                             diag::warn_impcast_string_literal_to_bool);
4646    if (Source->isFunctionType()) {
4647      // Warn on function to bool. Checks free functions and static member
4648      // functions. Weakly imported functions are excluded from the check,
4649      // since it's common to test their value to check whether the linker
4650      // found a definition for them.
4651      ValueDecl *D = 0;
4652      if (DeclRefExpr* R = dyn_cast<DeclRefExpr>(E)) {
4653        D = R->getDecl();
4654      } else if (MemberExpr *M = dyn_cast<MemberExpr>(E)) {
4655        D = M->getMemberDecl();
4656      }
4657
4658      if (D && !D->isWeak()) {
4659        if (FunctionDecl* F = dyn_cast<FunctionDecl>(D)) {
4660          S.Diag(E->getExprLoc(), diag::warn_impcast_function_to_bool)
4661            << F << E->getSourceRange() << SourceRange(CC);
4662          S.Diag(E->getExprLoc(), diag::note_function_to_bool_silence)
4663            << FixItHint::CreateInsertion(E->getExprLoc(), "&");
4664          QualType ReturnType;
4665          UnresolvedSet<4> NonTemplateOverloads;
4666          S.isExprCallable(*E, ReturnType, NonTemplateOverloads);
4667          if (!ReturnType.isNull()
4668              && ReturnType->isSpecificBuiltinType(BuiltinType::Bool))
4669            S.Diag(E->getExprLoc(), diag::note_function_to_bool_call)
4670              << FixItHint::CreateInsertion(
4671                 S.getPreprocessor().getLocForEndOfToken(E->getLocEnd()), "()");
4672          return;
4673        }
4674      }
4675    }
4676  }
4677
4678  // Strip vector types.
4679  if (isa<VectorType>(Source)) {
4680    if (!isa<VectorType>(Target)) {
4681      if (S.SourceMgr.isInSystemMacro(CC))
4682        return;
4683      return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_vector_scalar);
4684    }
4685
4686    // If the vector cast is cast between two vectors of the same size, it is
4687    // a bitcast, not a conversion.
4688    if (S.Context.getTypeSize(Source) == S.Context.getTypeSize(Target))
4689      return;
4690
4691    Source = cast<VectorType>(Source)->getElementType().getTypePtr();
4692    Target = cast<VectorType>(Target)->getElementType().getTypePtr();
4693  }
4694
4695  // Strip complex types.
4696  if (isa<ComplexType>(Source)) {
4697    if (!isa<ComplexType>(Target)) {
4698      if (S.SourceMgr.isInSystemMacro(CC))
4699        return;
4700
4701      return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_complex_scalar);
4702    }
4703
4704    Source = cast<ComplexType>(Source)->getElementType().getTypePtr();
4705    Target = cast<ComplexType>(Target)->getElementType().getTypePtr();
4706  }
4707
4708  const BuiltinType *SourceBT = dyn_cast<BuiltinType>(Source);
4709  const BuiltinType *TargetBT = dyn_cast<BuiltinType>(Target);
4710
4711  // If the source is floating point...
4712  if (SourceBT && SourceBT->isFloatingPoint()) {
4713    // ...and the target is floating point...
4714    if (TargetBT && TargetBT->isFloatingPoint()) {
4715      // ...then warn if we're dropping FP rank.
4716
4717      // Builtin FP kinds are ordered by increasing FP rank.
4718      if (SourceBT->getKind() > TargetBT->getKind()) {
4719        // Don't warn about float constants that are precisely
4720        // representable in the target type.
4721        Expr::EvalResult result;
4722        if (E->EvaluateAsRValue(result, S.Context)) {
4723          // Value might be a float, a float vector, or a float complex.
4724          if (IsSameFloatAfterCast(result.Val,
4725                   S.Context.getFloatTypeSemantics(QualType(TargetBT, 0)),
4726                   S.Context.getFloatTypeSemantics(QualType(SourceBT, 0))))
4727            return;
4728        }
4729
4730        if (S.SourceMgr.isInSystemMacro(CC))
4731          return;
4732
4733        DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_precision);
4734      }
4735      return;
4736    }
4737
4738    // If the target is integral, always warn.
4739    if (TargetBT && TargetBT->isInteger()) {
4740      if (S.SourceMgr.isInSystemMacro(CC))
4741        return;
4742
4743      Expr *InnerE = E->IgnoreParenImpCasts();
4744      // We also want to warn on, e.g., "int i = -1.234"
4745      if (UnaryOperator *UOp = dyn_cast<UnaryOperator>(InnerE))
4746        if (UOp->getOpcode() == UO_Minus || UOp->getOpcode() == UO_Plus)
4747          InnerE = UOp->getSubExpr()->IgnoreParenImpCasts();
4748
4749      if (FloatingLiteral *FL = dyn_cast<FloatingLiteral>(InnerE)) {
4750        DiagnoseFloatingLiteralImpCast(S, FL, T, CC);
4751      } else {
4752        DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_integer);
4753      }
4754    }
4755
4756    // If the target is bool, warn if expr is a function or method call.
4757    if (Target->isSpecificBuiltinType(BuiltinType::Bool) &&
4758        isa<CallExpr>(E)) {
4759      // Check last argument of function call to see if it is an
4760      // implicit cast from a type matching the type the result
4761      // is being cast to.
4762      CallExpr *CEx = cast<CallExpr>(E);
4763      unsigned NumArgs = CEx->getNumArgs();
4764      if (NumArgs > 0) {
4765        Expr *LastA = CEx->getArg(NumArgs - 1);
4766        Expr *InnerE = LastA->IgnoreParenImpCasts();
4767        const Type *InnerType =
4768          S.Context.getCanonicalType(InnerE->getType()).getTypePtr();
4769        if (isa<ImplicitCastExpr>(LastA) && (InnerType == Target)) {
4770          // Warn on this floating-point to bool conversion
4771          DiagnoseImpCast(S, E, T, CC,
4772                          diag::warn_impcast_floating_point_to_bool);
4773        }
4774      }
4775    }
4776    return;
4777  }
4778
4779  if ((E->isNullPointerConstant(S.Context, Expr::NPC_ValueDependentIsNotNull)
4780           == Expr::NPCK_GNUNull) && !Target->isAnyPointerType()
4781      && !Target->isBlockPointerType() && !Target->isMemberPointerType()) {
4782    SourceLocation Loc = E->getSourceRange().getBegin();
4783    if (Loc.isMacroID())
4784      Loc = S.SourceMgr.getImmediateExpansionRange(Loc).first;
4785    if (!Loc.isMacroID() || CC.isMacroID())
4786      S.Diag(Loc, diag::warn_impcast_null_pointer_to_integer)
4787          << T << clang::SourceRange(CC)
4788          << FixItHint::CreateReplacement(Loc, S.getFixItZeroLiteralForType(T));
4789  }
4790
4791  if (!Source->isIntegerType() || !Target->isIntegerType())
4792    return;
4793
4794  // TODO: remove this early return once the false positives for constant->bool
4795  // in templates, macros, etc, are reduced or removed.
4796  if (Target->isSpecificBuiltinType(BuiltinType::Bool))
4797    return;
4798
4799  IntRange SourceRange = GetExprRange(S.Context, E);
4800  IntRange TargetRange = IntRange::forTargetOfCanonicalType(S.Context, Target);
4801
4802  if (SourceRange.Width > TargetRange.Width) {
4803    // If the source is a constant, use a default-on diagnostic.
4804    // TODO: this should happen for bitfield stores, too.
4805    llvm::APSInt Value(32);
4806    if (E->isIntegerConstantExpr(Value, S.Context)) {
4807      if (S.SourceMgr.isInSystemMacro(CC))
4808        return;
4809
4810      std::string PrettySourceValue = Value.toString(10);
4811      std::string PrettyTargetValue = PrettyPrintInRange(Value, TargetRange);
4812
4813      S.DiagRuntimeBehavior(E->getExprLoc(), E,
4814        S.PDiag(diag::warn_impcast_integer_precision_constant)
4815            << PrettySourceValue << PrettyTargetValue
4816            << E->getType() << T << E->getSourceRange()
4817            << clang::SourceRange(CC));
4818      return;
4819    }
4820
4821    // People want to build with -Wshorten-64-to-32 and not -Wconversion.
4822    if (S.SourceMgr.isInSystemMacro(CC))
4823      return;
4824
4825    if (TargetRange.Width == 32 && S.Context.getIntWidth(E->getType()) == 64)
4826      return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_64_32,
4827                             /* pruneControlFlow */ true);
4828    return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_precision);
4829  }
4830
4831  if ((TargetRange.NonNegative && !SourceRange.NonNegative) ||
4832      (!TargetRange.NonNegative && SourceRange.NonNegative &&
4833       SourceRange.Width == TargetRange.Width)) {
4834
4835    if (S.SourceMgr.isInSystemMacro(CC))
4836      return;
4837
4838    unsigned DiagID = diag::warn_impcast_integer_sign;
4839
4840    // Traditionally, gcc has warned about this under -Wsign-compare.
4841    // We also want to warn about it in -Wconversion.
4842    // So if -Wconversion is off, use a completely identical diagnostic
4843    // in the sign-compare group.
4844    // The conditional-checking code will
4845    if (ICContext) {
4846      DiagID = diag::warn_impcast_integer_sign_conditional;
4847      *ICContext = true;
4848    }
4849
4850    return DiagnoseImpCast(S, E, T, CC, DiagID);
4851  }
4852
4853  // Diagnose conversions between different enumeration types.
4854  // In C, we pretend that the type of an EnumConstantDecl is its enumeration
4855  // type, to give us better diagnostics.
4856  QualType SourceType = E->getType();
4857  if (!S.getLangOpts().CPlusPlus) {
4858    if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
4859      if (EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(DRE->getDecl())) {
4860        EnumDecl *Enum = cast<EnumDecl>(ECD->getDeclContext());
4861        SourceType = S.Context.getTypeDeclType(Enum);
4862        Source = S.Context.getCanonicalType(SourceType).getTypePtr();
4863      }
4864  }
4865
4866  if (const EnumType *SourceEnum = Source->getAs<EnumType>())
4867    if (const EnumType *TargetEnum = Target->getAs<EnumType>())
4868      if ((SourceEnum->getDecl()->getIdentifier() ||
4869           SourceEnum->getDecl()->getTypedefNameForAnonDecl()) &&
4870          (TargetEnum->getDecl()->getIdentifier() ||
4871           TargetEnum->getDecl()->getTypedefNameForAnonDecl()) &&
4872          SourceEnum != TargetEnum) {
4873        if (S.SourceMgr.isInSystemMacro(CC))
4874          return;
4875
4876        return DiagnoseImpCast(S, E, SourceType, T, CC,
4877                               diag::warn_impcast_different_enum_types);
4878      }
4879
4880  return;
4881}
4882
4883void CheckConditionalOperator(Sema &S, ConditionalOperator *E,
4884                              SourceLocation CC, QualType T);
4885
4886void CheckConditionalOperand(Sema &S, Expr *E, QualType T,
4887                             SourceLocation CC, bool &ICContext) {
4888  E = E->IgnoreParenImpCasts();
4889
4890  if (isa<ConditionalOperator>(E))
4891    return CheckConditionalOperator(S, cast<ConditionalOperator>(E), CC, T);
4892
4893  AnalyzeImplicitConversions(S, E, CC);
4894  if (E->getType() != T)
4895    return CheckImplicitConversion(S, E, T, CC, &ICContext);
4896  return;
4897}
4898
4899void CheckConditionalOperator(Sema &S, ConditionalOperator *E,
4900                              SourceLocation CC, QualType T) {
4901  AnalyzeImplicitConversions(S, E->getCond(), CC);
4902
4903  bool Suspicious = false;
4904  CheckConditionalOperand(S, E->getTrueExpr(), T, CC, Suspicious);
4905  CheckConditionalOperand(S, E->getFalseExpr(), T, CC, Suspicious);
4906
4907  // If -Wconversion would have warned about either of the candidates
4908  // for a signedness conversion to the context type...
4909  if (!Suspicious) return;
4910
4911  // ...but it's currently ignored...
4912  if (S.Diags.getDiagnosticLevel(diag::warn_impcast_integer_sign_conditional,
4913                                 CC))
4914    return;
4915
4916  // ...then check whether it would have warned about either of the
4917  // candidates for a signedness conversion to the condition type.
4918  if (E->getType() == T) return;
4919
4920  Suspicious = false;
4921  CheckImplicitConversion(S, E->getTrueExpr()->IgnoreParenImpCasts(),
4922                          E->getType(), CC, &Suspicious);
4923  if (!Suspicious)
4924    CheckImplicitConversion(S, E->getFalseExpr()->IgnoreParenImpCasts(),
4925                            E->getType(), CC, &Suspicious);
4926}
4927
4928/// AnalyzeImplicitConversions - Find and report any interesting
4929/// implicit conversions in the given expression.  There are a couple
4930/// of competing diagnostics here, -Wconversion and -Wsign-compare.
4931void AnalyzeImplicitConversions(Sema &S, Expr *OrigE, SourceLocation CC) {
4932  QualType T = OrigE->getType();
4933  Expr *E = OrigE->IgnoreParenImpCasts();
4934
4935  if (E->isTypeDependent() || E->isValueDependent())
4936    return;
4937
4938  // For conditional operators, we analyze the arguments as if they
4939  // were being fed directly into the output.
4940  if (isa<ConditionalOperator>(E)) {
4941    ConditionalOperator *CO = cast<ConditionalOperator>(E);
4942    CheckConditionalOperator(S, CO, CC, T);
4943    return;
4944  }
4945
4946  // Check implicit argument conversions for function calls.
4947  if (CallExpr *Call = dyn_cast<CallExpr>(E))
4948    CheckImplicitArgumentConversions(S, Call, CC);
4949
4950  // Go ahead and check any implicit conversions we might have skipped.
4951  // The non-canonical typecheck is just an optimization;
4952  // CheckImplicitConversion will filter out dead implicit conversions.
4953  if (E->getType() != T)
4954    CheckImplicitConversion(S, E, T, CC);
4955
4956  // Now continue drilling into this expression.
4957
4958  // Skip past explicit casts.
4959  if (isa<ExplicitCastExpr>(E)) {
4960    E = cast<ExplicitCastExpr>(E)->getSubExpr()->IgnoreParenImpCasts();
4961    return AnalyzeImplicitConversions(S, E, CC);
4962  }
4963
4964  if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {
4965    // Do a somewhat different check with comparison operators.
4966    if (BO->isComparisonOp())
4967      return AnalyzeComparison(S, BO);
4968
4969    // And with simple assignments.
4970    if (BO->getOpcode() == BO_Assign)
4971      return AnalyzeAssignment(S, BO);
4972  }
4973
4974  // These break the otherwise-useful invariant below.  Fortunately,
4975  // we don't really need to recurse into them, because any internal
4976  // expressions should have been analyzed already when they were
4977  // built into statements.
4978  if (isa<StmtExpr>(E)) return;
4979
4980  // Don't descend into unevaluated contexts.
4981  if (isa<UnaryExprOrTypeTraitExpr>(E)) return;
4982
4983  // Now just recurse over the expression's children.
4984  CC = E->getExprLoc();
4985  BinaryOperator *BO = dyn_cast<BinaryOperator>(E);
4986  bool IsLogicalOperator = BO && BO->isLogicalOp();
4987  for (Stmt::child_range I = E->children(); I; ++I) {
4988    Expr *ChildExpr = dyn_cast_or_null<Expr>(*I);
4989    if (!ChildExpr)
4990      continue;
4991
4992    if (IsLogicalOperator &&
4993        isa<StringLiteral>(ChildExpr->IgnoreParenImpCasts()))
4994      // Ignore checking string literals that are in logical operators.
4995      continue;
4996    AnalyzeImplicitConversions(S, ChildExpr, CC);
4997  }
4998}
4999
5000} // end anonymous namespace
5001
5002/// Diagnoses "dangerous" implicit conversions within the given
5003/// expression (which is a full expression).  Implements -Wconversion
5004/// and -Wsign-compare.
5005///
5006/// \param CC the "context" location of the implicit conversion, i.e.
5007///   the most location of the syntactic entity requiring the implicit
5008///   conversion
5009void Sema::CheckImplicitConversions(Expr *E, SourceLocation CC) {
5010  // Don't diagnose in unevaluated contexts.
5011  if (isUnevaluatedContext())
5012    return;
5013
5014  // Don't diagnose for value- or type-dependent expressions.
5015  if (E->isTypeDependent() || E->isValueDependent())
5016    return;
5017
5018  // Check for array bounds violations in cases where the check isn't triggered
5019  // elsewhere for other Expr types (like BinaryOperators), e.g. when an
5020  // ArraySubscriptExpr is on the RHS of a variable initialization.
5021  CheckArrayAccess(E);
5022
5023  // This is not the right CC for (e.g.) a variable initialization.
5024  AnalyzeImplicitConversions(*this, E, CC);
5025}
5026
5027void Sema::CheckBitFieldInitialization(SourceLocation InitLoc,
5028                                       FieldDecl *BitField,
5029                                       Expr *Init) {
5030  (void) AnalyzeBitFieldAssignment(*this, BitField, Init, InitLoc);
5031}
5032
5033/// CheckParmsForFunctionDef - Check that the parameters of the given
5034/// function are appropriate for the definition of a function. This
5035/// takes care of any checks that cannot be performed on the
5036/// declaration itself, e.g., that the types of each of the function
5037/// parameters are complete.
5038bool Sema::CheckParmsForFunctionDef(ParmVarDecl **P, ParmVarDecl **PEnd,
5039                                    bool CheckParameterNames) {
5040  bool HasInvalidParm = false;
5041  for (; P != PEnd; ++P) {
5042    ParmVarDecl *Param = *P;
5043
5044    // C99 6.7.5.3p4: the parameters in a parameter type list in a
5045    // function declarator that is part of a function definition of
5046    // that function shall not have incomplete type.
5047    //
5048    // This is also C++ [dcl.fct]p6.
5049    if (!Param->isInvalidDecl() &&
5050        RequireCompleteType(Param->getLocation(), Param->getType(),
5051                            diag::err_typecheck_decl_incomplete_type)) {
5052      Param->setInvalidDecl();
5053      HasInvalidParm = true;
5054    }
5055
5056    // C99 6.9.1p5: If the declarator includes a parameter type list, the
5057    // declaration of each parameter shall include an identifier.
5058    if (CheckParameterNames &&
5059        Param->getIdentifier() == 0 &&
5060        !Param->isImplicit() &&
5061        !getLangOpts().CPlusPlus)
5062      Diag(Param->getLocation(), diag::err_parameter_name_omitted);
5063
5064    // C99 6.7.5.3p12:
5065    //   If the function declarator is not part of a definition of that
5066    //   function, parameters may have incomplete type and may use the [*]
5067    //   notation in their sequences of declarator specifiers to specify
5068    //   variable length array types.
5069    QualType PType = Param->getOriginalType();
5070    if (const ArrayType *AT = Context.getAsArrayType(PType)) {
5071      if (AT->getSizeModifier() == ArrayType::Star) {
5072        // FIXME: This diagnosic should point the '[*]' if source-location
5073        // information is added for it.
5074        Diag(Param->getLocation(), diag::err_array_star_in_function_definition);
5075      }
5076    }
5077  }
5078
5079  return HasInvalidParm;
5080}
5081
5082/// CheckCastAlign - Implements -Wcast-align, which warns when a
5083/// pointer cast increases the alignment requirements.
5084void Sema::CheckCastAlign(Expr *Op, QualType T, SourceRange TRange) {
5085  // This is actually a lot of work to potentially be doing on every
5086  // cast; don't do it if we're ignoring -Wcast_align (as is the default).
5087  if (getDiagnostics().getDiagnosticLevel(diag::warn_cast_align,
5088                                          TRange.getBegin())
5089        == DiagnosticsEngine::Ignored)
5090    return;
5091
5092  // Ignore dependent types.
5093  if (T->isDependentType() || Op->getType()->isDependentType())
5094    return;
5095
5096  // Require that the destination be a pointer type.
5097  const PointerType *DestPtr = T->getAs<PointerType>();
5098  if (!DestPtr) return;
5099
5100  // If the destination has alignment 1, we're done.
5101  QualType DestPointee = DestPtr->getPointeeType();
5102  if (DestPointee->isIncompleteType()) return;
5103  CharUnits DestAlign = Context.getTypeAlignInChars(DestPointee);
5104  if (DestAlign.isOne()) return;
5105
5106  // Require that the source be a pointer type.
5107  const PointerType *SrcPtr = Op->getType()->getAs<PointerType>();
5108  if (!SrcPtr) return;
5109  QualType SrcPointee = SrcPtr->getPointeeType();
5110
5111  // Whitelist casts from cv void*.  We already implicitly
5112  // whitelisted casts to cv void*, since they have alignment 1.
5113  // Also whitelist casts involving incomplete types, which implicitly
5114  // includes 'void'.
5115  if (SrcPointee->isIncompleteType()) return;
5116
5117  CharUnits SrcAlign = Context.getTypeAlignInChars(SrcPointee);
5118  if (SrcAlign >= DestAlign) return;
5119
5120  Diag(TRange.getBegin(), diag::warn_cast_align)
5121    << Op->getType() << T
5122    << static_cast<unsigned>(SrcAlign.getQuantity())
5123    << static_cast<unsigned>(DestAlign.getQuantity())
5124    << TRange << Op->getSourceRange();
5125}
5126
5127static const Type* getElementType(const Expr *BaseExpr) {
5128  const Type* EltType = BaseExpr->getType().getTypePtr();
5129  if (EltType->isAnyPointerType())
5130    return EltType->getPointeeType().getTypePtr();
5131  else if (EltType->isArrayType())
5132    return EltType->getBaseElementTypeUnsafe();
5133  return EltType;
5134}
5135
5136/// \brief Check whether this array fits the idiom of a size-one tail padded
5137/// array member of a struct.
5138///
5139/// We avoid emitting out-of-bounds access warnings for such arrays as they are
5140/// commonly used to emulate flexible arrays in C89 code.
5141static bool IsTailPaddedMemberArray(Sema &S, llvm::APInt Size,
5142                                    const NamedDecl *ND) {
5143  if (Size != 1 || !ND) return false;
5144
5145  const FieldDecl *FD = dyn_cast<FieldDecl>(ND);
5146  if (!FD) return false;
5147
5148  // Don't consider sizes resulting from macro expansions or template argument
5149  // substitution to form C89 tail-padded arrays.
5150
5151  TypeSourceInfo *TInfo = FD->getTypeSourceInfo();
5152  while (TInfo) {
5153    TypeLoc TL = TInfo->getTypeLoc();
5154    // Look through typedefs.
5155    const TypedefTypeLoc *TTL = dyn_cast<TypedefTypeLoc>(&TL);
5156    if (TTL) {
5157      const TypedefNameDecl *TDL = TTL->getTypedefNameDecl();
5158      TInfo = TDL->getTypeSourceInfo();
5159      continue;
5160    }
5161    ConstantArrayTypeLoc CTL = cast<ConstantArrayTypeLoc>(TL);
5162    const Expr *SizeExpr = dyn_cast<IntegerLiteral>(CTL.getSizeExpr());
5163    if (!SizeExpr || SizeExpr->getExprLoc().isMacroID())
5164      return false;
5165    break;
5166  }
5167
5168  const RecordDecl *RD = dyn_cast<RecordDecl>(FD->getDeclContext());
5169  if (!RD) return false;
5170  if (RD->isUnion()) return false;
5171  if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(RD)) {
5172    if (!CRD->isStandardLayout()) return false;
5173  }
5174
5175  // See if this is the last field decl in the record.
5176  const Decl *D = FD;
5177  while ((D = D->getNextDeclInContext()))
5178    if (isa<FieldDecl>(D))
5179      return false;
5180  return true;
5181}
5182
5183void Sema::CheckArrayAccess(const Expr *BaseExpr, const Expr *IndexExpr,
5184                            const ArraySubscriptExpr *ASE,
5185                            bool AllowOnePastEnd, bool IndexNegated) {
5186  IndexExpr = IndexExpr->IgnoreParenImpCasts();
5187  if (IndexExpr->isValueDependent())
5188    return;
5189
5190  const Type *EffectiveType = getElementType(BaseExpr);
5191  BaseExpr = BaseExpr->IgnoreParenCasts();
5192  const ConstantArrayType *ArrayTy =
5193    Context.getAsConstantArrayType(BaseExpr->getType());
5194  if (!ArrayTy)
5195    return;
5196
5197  llvm::APSInt index;
5198  if (!IndexExpr->EvaluateAsInt(index, Context))
5199    return;
5200  if (IndexNegated)
5201    index = -index;
5202
5203  const NamedDecl *ND = NULL;
5204  if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr))
5205    ND = dyn_cast<NamedDecl>(DRE->getDecl());
5206  if (const MemberExpr *ME = dyn_cast<MemberExpr>(BaseExpr))
5207    ND = dyn_cast<NamedDecl>(ME->getMemberDecl());
5208
5209  if (index.isUnsigned() || !index.isNegative()) {
5210    llvm::APInt size = ArrayTy->getSize();
5211    if (!size.isStrictlyPositive())
5212      return;
5213
5214    const Type* BaseType = getElementType(BaseExpr);
5215    if (BaseType != EffectiveType) {
5216      // Make sure we're comparing apples to apples when comparing index to size
5217      uint64_t ptrarith_typesize = Context.getTypeSize(EffectiveType);
5218      uint64_t array_typesize = Context.getTypeSize(BaseType);
5219      // Handle ptrarith_typesize being zero, such as when casting to void*
5220      if (!ptrarith_typesize) ptrarith_typesize = 1;
5221      if (ptrarith_typesize != array_typesize) {
5222        // There's a cast to a different size type involved
5223        uint64_t ratio = array_typesize / ptrarith_typesize;
5224        // TODO: Be smarter about handling cases where array_typesize is not a
5225        // multiple of ptrarith_typesize
5226        if (ptrarith_typesize * ratio == array_typesize)
5227          size *= llvm::APInt(size.getBitWidth(), ratio);
5228      }
5229    }
5230
5231    if (size.getBitWidth() > index.getBitWidth())
5232      index = index.zext(size.getBitWidth());
5233    else if (size.getBitWidth() < index.getBitWidth())
5234      size = size.zext(index.getBitWidth());
5235
5236    // For array subscripting the index must be less than size, but for pointer
5237    // arithmetic also allow the index (offset) to be equal to size since
5238    // computing the next address after the end of the array is legal and
5239    // commonly done e.g. in C++ iterators and range-based for loops.
5240    if (AllowOnePastEnd ? index.ule(size) : index.ult(size))
5241      return;
5242
5243    // Also don't warn for arrays of size 1 which are members of some
5244    // structure. These are often used to approximate flexible arrays in C89
5245    // code.
5246    if (IsTailPaddedMemberArray(*this, size, ND))
5247      return;
5248
5249    // Suppress the warning if the subscript expression (as identified by the
5250    // ']' location) and the index expression are both from macro expansions
5251    // within a system header.
5252    if (ASE) {
5253      SourceLocation RBracketLoc = SourceMgr.getSpellingLoc(
5254          ASE->getRBracketLoc());
5255      if (SourceMgr.isInSystemHeader(RBracketLoc)) {
5256        SourceLocation IndexLoc = SourceMgr.getSpellingLoc(
5257            IndexExpr->getLocStart());
5258        if (SourceMgr.isFromSameFile(RBracketLoc, IndexLoc))
5259          return;
5260      }
5261    }
5262
5263    unsigned DiagID = diag::warn_ptr_arith_exceeds_bounds;
5264    if (ASE)
5265      DiagID = diag::warn_array_index_exceeds_bounds;
5266
5267    DiagRuntimeBehavior(BaseExpr->getLocStart(), BaseExpr,
5268                        PDiag(DiagID) << index.toString(10, true)
5269                          << size.toString(10, true)
5270                          << (unsigned)size.getLimitedValue(~0U)
5271                          << IndexExpr->getSourceRange());
5272  } else {
5273    unsigned DiagID = diag::warn_array_index_precedes_bounds;
5274    if (!ASE) {
5275      DiagID = diag::warn_ptr_arith_precedes_bounds;
5276      if (index.isNegative()) index = -index;
5277    }
5278
5279    DiagRuntimeBehavior(BaseExpr->getLocStart(), BaseExpr,
5280                        PDiag(DiagID) << index.toString(10, true)
5281                          << IndexExpr->getSourceRange());
5282  }
5283
5284  if (!ND) {
5285    // Try harder to find a NamedDecl to point at in the note.
5286    while (const ArraySubscriptExpr *ASE =
5287           dyn_cast<ArraySubscriptExpr>(BaseExpr))
5288      BaseExpr = ASE->getBase()->IgnoreParenCasts();
5289    if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr))
5290      ND = dyn_cast<NamedDecl>(DRE->getDecl());
5291    if (const MemberExpr *ME = dyn_cast<MemberExpr>(BaseExpr))
5292      ND = dyn_cast<NamedDecl>(ME->getMemberDecl());
5293  }
5294
5295  if (ND)
5296    DiagRuntimeBehavior(ND->getLocStart(), BaseExpr,
5297                        PDiag(diag::note_array_index_out_of_bounds)
5298                          << ND->getDeclName());
5299}
5300
5301void Sema::CheckArrayAccess(const Expr *expr) {
5302  int AllowOnePastEnd = 0;
5303  while (expr) {
5304    expr = expr->IgnoreParenImpCasts();
5305    switch (expr->getStmtClass()) {
5306      case Stmt::ArraySubscriptExprClass: {
5307        const ArraySubscriptExpr *ASE = cast<ArraySubscriptExpr>(expr);
5308        CheckArrayAccess(ASE->getBase(), ASE->getIdx(), ASE,
5309                         AllowOnePastEnd > 0);
5310        return;
5311      }
5312      case Stmt::UnaryOperatorClass: {
5313        // Only unwrap the * and & unary operators
5314        const UnaryOperator *UO = cast<UnaryOperator>(expr);
5315        expr = UO->getSubExpr();
5316        switch (UO->getOpcode()) {
5317          case UO_AddrOf:
5318            AllowOnePastEnd++;
5319            break;
5320          case UO_Deref:
5321            AllowOnePastEnd--;
5322            break;
5323          default:
5324            return;
5325        }
5326        break;
5327      }
5328      case Stmt::ConditionalOperatorClass: {
5329        const ConditionalOperator *cond = cast<ConditionalOperator>(expr);
5330        if (const Expr *lhs = cond->getLHS())
5331          CheckArrayAccess(lhs);
5332        if (const Expr *rhs = cond->getRHS())
5333          CheckArrayAccess(rhs);
5334        return;
5335      }
5336      default:
5337        return;
5338    }
5339  }
5340}
5341
5342//===--- CHECK: Objective-C retain cycles ----------------------------------//
5343
5344namespace {
5345  struct RetainCycleOwner {
5346    RetainCycleOwner() : Variable(0), Indirect(false) {}
5347    VarDecl *Variable;
5348    SourceRange Range;
5349    SourceLocation Loc;
5350    bool Indirect;
5351
5352    void setLocsFrom(Expr *e) {
5353      Loc = e->getExprLoc();
5354      Range = e->getSourceRange();
5355    }
5356  };
5357}
5358
5359/// Consider whether capturing the given variable can possibly lead to
5360/// a retain cycle.
5361static bool considerVariable(VarDecl *var, Expr *ref, RetainCycleOwner &owner) {
5362  // In ARC, it's captured strongly iff the variable has __strong
5363  // lifetime.  In MRR, it's captured strongly if the variable is
5364  // __block and has an appropriate type.
5365  if (var->getType().getObjCLifetime() != Qualifiers::OCL_Strong)
5366    return false;
5367
5368  owner.Variable = var;
5369  if (ref)
5370    owner.setLocsFrom(ref);
5371  return true;
5372}
5373
5374static bool findRetainCycleOwner(Sema &S, Expr *e, RetainCycleOwner &owner) {
5375  while (true) {
5376    e = e->IgnoreParens();
5377    if (CastExpr *cast = dyn_cast<CastExpr>(e)) {
5378      switch (cast->getCastKind()) {
5379      case CK_BitCast:
5380      case CK_LValueBitCast:
5381      case CK_LValueToRValue:
5382      case CK_ARCReclaimReturnedObject:
5383        e = cast->getSubExpr();
5384        continue;
5385
5386      default:
5387        return false;
5388      }
5389    }
5390
5391    if (ObjCIvarRefExpr *ref = dyn_cast<ObjCIvarRefExpr>(e)) {
5392      ObjCIvarDecl *ivar = ref->getDecl();
5393      if (ivar->getType().getObjCLifetime() != Qualifiers::OCL_Strong)
5394        return false;
5395
5396      // Try to find a retain cycle in the base.
5397      if (!findRetainCycleOwner(S, ref->getBase(), owner))
5398        return false;
5399
5400      if (ref->isFreeIvar()) owner.setLocsFrom(ref);
5401      owner.Indirect = true;
5402      return true;
5403    }
5404
5405    if (DeclRefExpr *ref = dyn_cast<DeclRefExpr>(e)) {
5406      VarDecl *var = dyn_cast<VarDecl>(ref->getDecl());
5407      if (!var) return false;
5408      return considerVariable(var, ref, owner);
5409    }
5410
5411    if (MemberExpr *member = dyn_cast<MemberExpr>(e)) {
5412      if (member->isArrow()) return false;
5413
5414      // Don't count this as an indirect ownership.
5415      e = member->getBase();
5416      continue;
5417    }
5418
5419    if (PseudoObjectExpr *pseudo = dyn_cast<PseudoObjectExpr>(e)) {
5420      // Only pay attention to pseudo-objects on property references.
5421      ObjCPropertyRefExpr *pre
5422        = dyn_cast<ObjCPropertyRefExpr>(pseudo->getSyntacticForm()
5423                                              ->IgnoreParens());
5424      if (!pre) return false;
5425      if (pre->isImplicitProperty()) return false;
5426      ObjCPropertyDecl *property = pre->getExplicitProperty();
5427      if (!property->isRetaining() &&
5428          !(property->getPropertyIvarDecl() &&
5429            property->getPropertyIvarDecl()->getType()
5430              .getObjCLifetime() == Qualifiers::OCL_Strong))
5431          return false;
5432
5433      owner.Indirect = true;
5434      if (pre->isSuperReceiver()) {
5435        owner.Variable = S.getCurMethodDecl()->getSelfDecl();
5436        if (!owner.Variable)
5437          return false;
5438        owner.Loc = pre->getLocation();
5439        owner.Range = pre->getSourceRange();
5440        return true;
5441      }
5442      e = const_cast<Expr*>(cast<OpaqueValueExpr>(pre->getBase())
5443                              ->getSourceExpr());
5444      continue;
5445    }
5446
5447    // Array ivars?
5448
5449    return false;
5450  }
5451}
5452
5453namespace {
5454  struct FindCaptureVisitor : EvaluatedExprVisitor<FindCaptureVisitor> {
5455    FindCaptureVisitor(ASTContext &Context, VarDecl *variable)
5456      : EvaluatedExprVisitor<FindCaptureVisitor>(Context),
5457        Variable(variable), Capturer(0) {}
5458
5459    VarDecl *Variable;
5460    Expr *Capturer;
5461
5462    void VisitDeclRefExpr(DeclRefExpr *ref) {
5463      if (ref->getDecl() == Variable && !Capturer)
5464        Capturer = ref;
5465    }
5466
5467    void VisitObjCIvarRefExpr(ObjCIvarRefExpr *ref) {
5468      if (Capturer) return;
5469      Visit(ref->getBase());
5470      if (Capturer && ref->isFreeIvar())
5471        Capturer = ref;
5472    }
5473
5474    void VisitBlockExpr(BlockExpr *block) {
5475      // Look inside nested blocks
5476      if (block->getBlockDecl()->capturesVariable(Variable))
5477        Visit(block->getBlockDecl()->getBody());
5478    }
5479
5480    void VisitOpaqueValueExpr(OpaqueValueExpr *OVE) {
5481      if (Capturer) return;
5482      if (OVE->getSourceExpr())
5483        Visit(OVE->getSourceExpr());
5484    }
5485  };
5486}
5487
5488/// Check whether the given argument is a block which captures a
5489/// variable.
5490static Expr *findCapturingExpr(Sema &S, Expr *e, RetainCycleOwner &owner) {
5491  assert(owner.Variable && owner.Loc.isValid());
5492
5493  e = e->IgnoreParenCasts();
5494
5495  // Look through [^{...} copy] and Block_copy(^{...}).
5496  if (ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(e)) {
5497    Selector Cmd = ME->getSelector();
5498    if (Cmd.isUnarySelector() && Cmd.getNameForSlot(0) == "copy") {
5499      e = ME->getInstanceReceiver();
5500      if (!e)
5501        return 0;
5502      e = e->IgnoreParenCasts();
5503    }
5504  } else if (CallExpr *CE = dyn_cast<CallExpr>(e)) {
5505    if (CE->getNumArgs() == 1) {
5506      FunctionDecl *Fn = dyn_cast_or_null<FunctionDecl>(CE->getCalleeDecl());
5507      if (Fn && Fn->getIdentifier()->isStr("_Block_copy"))
5508        e = CE->getArg(0)->IgnoreParenCasts();
5509    }
5510  }
5511
5512  BlockExpr *block = dyn_cast<BlockExpr>(e);
5513  if (!block || !block->getBlockDecl()->capturesVariable(owner.Variable))
5514    return 0;
5515
5516  FindCaptureVisitor visitor(S.Context, owner.Variable);
5517  visitor.Visit(block->getBlockDecl()->getBody());
5518  return visitor.Capturer;
5519}
5520
5521static void diagnoseRetainCycle(Sema &S, Expr *capturer,
5522                                RetainCycleOwner &owner) {
5523  assert(capturer);
5524  assert(owner.Variable && owner.Loc.isValid());
5525
5526  S.Diag(capturer->getExprLoc(), diag::warn_arc_retain_cycle)
5527    << owner.Variable << capturer->getSourceRange();
5528  S.Diag(owner.Loc, diag::note_arc_retain_cycle_owner)
5529    << owner.Indirect << owner.Range;
5530}
5531
5532/// Check for a keyword selector that starts with the word 'add' or
5533/// 'set'.
5534static bool isSetterLikeSelector(Selector sel) {
5535  if (sel.isUnarySelector()) return false;
5536
5537  StringRef str = sel.getNameForSlot(0);
5538  while (!str.empty() && str.front() == '_') str = str.substr(1);
5539  if (str.startswith("set"))
5540    str = str.substr(3);
5541  else if (str.startswith("add")) {
5542    // Specially whitelist 'addOperationWithBlock:'.
5543    if (sel.getNumArgs() == 1 && str.startswith("addOperationWithBlock"))
5544      return false;
5545    str = str.substr(3);
5546  }
5547  else
5548    return false;
5549
5550  if (str.empty()) return true;
5551  return !islower(str.front());
5552}
5553
5554/// Check a message send to see if it's likely to cause a retain cycle.
5555void Sema::checkRetainCycles(ObjCMessageExpr *msg) {
5556  // Only check instance methods whose selector looks like a setter.
5557  if (!msg->isInstanceMessage() || !isSetterLikeSelector(msg->getSelector()))
5558    return;
5559
5560  // Try to find a variable that the receiver is strongly owned by.
5561  RetainCycleOwner owner;
5562  if (msg->getReceiverKind() == ObjCMessageExpr::Instance) {
5563    if (!findRetainCycleOwner(*this, msg->getInstanceReceiver(), owner))
5564      return;
5565  } else {
5566    assert(msg->getReceiverKind() == ObjCMessageExpr::SuperInstance);
5567    owner.Variable = getCurMethodDecl()->getSelfDecl();
5568    owner.Loc = msg->getSuperLoc();
5569    owner.Range = msg->getSuperLoc();
5570  }
5571
5572  // Check whether the receiver is captured by any of the arguments.
5573  for (unsigned i = 0, e = msg->getNumArgs(); i != e; ++i)
5574    if (Expr *capturer = findCapturingExpr(*this, msg->getArg(i), owner))
5575      return diagnoseRetainCycle(*this, capturer, owner);
5576}
5577
5578/// Check a property assign to see if it's likely to cause a retain cycle.
5579void Sema::checkRetainCycles(Expr *receiver, Expr *argument) {
5580  RetainCycleOwner owner;
5581  if (!findRetainCycleOwner(*this, receiver, owner))
5582    return;
5583
5584  if (Expr *capturer = findCapturingExpr(*this, argument, owner))
5585    diagnoseRetainCycle(*this, capturer, owner);
5586}
5587
5588void Sema::checkRetainCycles(VarDecl *Var, Expr *Init) {
5589  RetainCycleOwner Owner;
5590  if (!considerVariable(Var, /*DeclRefExpr=*/0, Owner))
5591    return;
5592
5593  // Because we don't have an expression for the variable, we have to set the
5594  // location explicitly here.
5595  Owner.Loc = Var->getLocation();
5596  Owner.Range = Var->getSourceRange();
5597
5598  if (Expr *Capturer = findCapturingExpr(*this, Init, Owner))
5599    diagnoseRetainCycle(*this, Capturer, Owner);
5600}
5601
5602bool Sema::checkUnsafeAssigns(SourceLocation Loc,
5603                              QualType LHS, Expr *RHS) {
5604  Qualifiers::ObjCLifetime LT = LHS.getObjCLifetime();
5605  if (LT != Qualifiers::OCL_Weak && LT != Qualifiers::OCL_ExplicitNone)
5606    return false;
5607  // strip off any implicit cast added to get to the one arc-specific
5608  while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) {
5609    if (cast->getCastKind() == CK_ARCConsumeObject) {
5610      Diag(Loc, diag::warn_arc_retained_assign)
5611        << (LT == Qualifiers::OCL_ExplicitNone) << 1
5612        << RHS->getSourceRange();
5613      return true;
5614    }
5615    RHS = cast->getSubExpr();
5616  }
5617  return false;
5618}
5619
5620void Sema::checkUnsafeExprAssigns(SourceLocation Loc,
5621                              Expr *LHS, Expr *RHS) {
5622  QualType LHSType;
5623  // PropertyRef on LHS type need be directly obtained from
5624  // its declaration as it has a PsuedoType.
5625  ObjCPropertyRefExpr *PRE
5626    = dyn_cast<ObjCPropertyRefExpr>(LHS->IgnoreParens());
5627  if (PRE && !PRE->isImplicitProperty()) {
5628    const ObjCPropertyDecl *PD = PRE->getExplicitProperty();
5629    if (PD)
5630      LHSType = PD->getType();
5631  }
5632
5633  if (LHSType.isNull())
5634    LHSType = LHS->getType();
5635  if (checkUnsafeAssigns(Loc, LHSType, RHS))
5636    return;
5637  Qualifiers::ObjCLifetime LT = LHSType.getObjCLifetime();
5638  // FIXME. Check for other life times.
5639  if (LT != Qualifiers::OCL_None)
5640    return;
5641
5642  if (PRE) {
5643    if (PRE->isImplicitProperty())
5644      return;
5645    const ObjCPropertyDecl *PD = PRE->getExplicitProperty();
5646    if (!PD)
5647      return;
5648
5649    unsigned Attributes = PD->getPropertyAttributes();
5650    if (Attributes & ObjCPropertyDecl::OBJC_PR_assign) {
5651      // when 'assign' attribute was not explicitly specified
5652      // by user, ignore it and rely on property type itself
5653      // for lifetime info.
5654      unsigned AsWrittenAttr = PD->getPropertyAttributesAsWritten();
5655      if (!(AsWrittenAttr & ObjCPropertyDecl::OBJC_PR_assign) &&
5656          LHSType->isObjCRetainableType())
5657        return;
5658
5659      while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) {
5660        if (cast->getCastKind() == CK_ARCConsumeObject) {
5661          Diag(Loc, diag::warn_arc_retained_property_assign)
5662          << RHS->getSourceRange();
5663          return;
5664        }
5665        RHS = cast->getSubExpr();
5666      }
5667    }
5668    else if (Attributes & ObjCPropertyDecl::OBJC_PR_weak) {
5669      while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) {
5670        if (cast->getCastKind() == CK_ARCConsumeObject) {
5671          Diag(Loc, diag::warn_arc_retained_assign)
5672          << 0 << 0<< RHS->getSourceRange();
5673          return;
5674        }
5675        RHS = cast->getSubExpr();
5676      }
5677    }
5678  }
5679}
5680
5681//===--- CHECK: Empty statement body (-Wempty-body) ---------------------===//
5682
5683namespace {
5684bool ShouldDiagnoseEmptyStmtBody(const SourceManager &SourceMgr,
5685                                 SourceLocation StmtLoc,
5686                                 const NullStmt *Body) {
5687  // Do not warn if the body is a macro that expands to nothing, e.g:
5688  //
5689  // #define CALL(x)
5690  // if (condition)
5691  //   CALL(0);
5692  //
5693  if (Body->hasLeadingEmptyMacro())
5694    return false;
5695
5696  // Get line numbers of statement and body.
5697  bool StmtLineInvalid;
5698  unsigned StmtLine = SourceMgr.getSpellingLineNumber(StmtLoc,
5699                                                      &StmtLineInvalid);
5700  if (StmtLineInvalid)
5701    return false;
5702
5703  bool BodyLineInvalid;
5704  unsigned BodyLine = SourceMgr.getSpellingLineNumber(Body->getSemiLoc(),
5705                                                      &BodyLineInvalid);
5706  if (BodyLineInvalid)
5707    return false;
5708
5709  // Warn if null statement and body are on the same line.
5710  if (StmtLine != BodyLine)
5711    return false;
5712
5713  return true;
5714}
5715} // Unnamed namespace
5716
5717void Sema::DiagnoseEmptyStmtBody(SourceLocation StmtLoc,
5718                                 const Stmt *Body,
5719                                 unsigned DiagID) {
5720  // Since this is a syntactic check, don't emit diagnostic for template
5721  // instantiations, this just adds noise.
5722  if (CurrentInstantiationScope)
5723    return;
5724
5725  // The body should be a null statement.
5726  const NullStmt *NBody = dyn_cast<NullStmt>(Body);
5727  if (!NBody)
5728    return;
5729
5730  // Do the usual checks.
5731  if (!ShouldDiagnoseEmptyStmtBody(SourceMgr, StmtLoc, NBody))
5732    return;
5733
5734  Diag(NBody->getSemiLoc(), DiagID);
5735  Diag(NBody->getSemiLoc(), diag::note_empty_body_on_separate_line);
5736}
5737
5738void Sema::DiagnoseEmptyLoopBody(const Stmt *S,
5739                                 const Stmt *PossibleBody) {
5740  assert(!CurrentInstantiationScope); // Ensured by caller
5741
5742  SourceLocation StmtLoc;
5743  const Stmt *Body;
5744  unsigned DiagID;
5745  if (const ForStmt *FS = dyn_cast<ForStmt>(S)) {
5746    StmtLoc = FS->getRParenLoc();
5747    Body = FS->getBody();
5748    DiagID = diag::warn_empty_for_body;
5749  } else if (const WhileStmt *WS = dyn_cast<WhileStmt>(S)) {
5750    StmtLoc = WS->getCond()->getSourceRange().getEnd();
5751    Body = WS->getBody();
5752    DiagID = diag::warn_empty_while_body;
5753  } else
5754    return; // Neither `for' nor `while'.
5755
5756  // The body should be a null statement.
5757  const NullStmt *NBody = dyn_cast<NullStmt>(Body);
5758  if (!NBody)
5759    return;
5760
5761  // Skip expensive checks if diagnostic is disabled.
5762  if (Diags.getDiagnosticLevel(DiagID, NBody->getSemiLoc()) ==
5763          DiagnosticsEngine::Ignored)
5764    return;
5765
5766  // Do the usual checks.
5767  if (!ShouldDiagnoseEmptyStmtBody(SourceMgr, StmtLoc, NBody))
5768    return;
5769
5770  // `for(...);' and `while(...);' are popular idioms, so in order to keep
5771  // noise level low, emit diagnostics only if for/while is followed by a
5772  // CompoundStmt, e.g.:
5773  //    for (int i = 0; i < n; i++);
5774  //    {
5775  //      a(i);
5776  //    }
5777  // or if for/while is followed by a statement with more indentation
5778  // than for/while itself:
5779  //    for (int i = 0; i < n; i++);
5780  //      a(i);
5781  bool ProbableTypo = isa<CompoundStmt>(PossibleBody);
5782  if (!ProbableTypo) {
5783    bool BodyColInvalid;
5784    unsigned BodyCol = SourceMgr.getPresumedColumnNumber(
5785                             PossibleBody->getLocStart(),
5786                             &BodyColInvalid);
5787    if (BodyColInvalid)
5788      return;
5789
5790    bool StmtColInvalid;
5791    unsigned StmtCol = SourceMgr.getPresumedColumnNumber(
5792                             S->getLocStart(),
5793                             &StmtColInvalid);
5794    if (StmtColInvalid)
5795      return;
5796
5797    if (BodyCol > StmtCol)
5798      ProbableTypo = true;
5799  }
5800
5801  if (ProbableTypo) {
5802    Diag(NBody->getSemiLoc(), DiagID);
5803    Diag(NBody->getSemiLoc(), diag::note_empty_body_on_separate_line);
5804  }
5805}
5806
5807//===--- Layout compatibility ----------------------------------------------//
5808
5809namespace {
5810
5811bool isLayoutCompatible(ASTContext &C, QualType T1, QualType T2);
5812
5813/// \brief Check if two enumeration types are layout-compatible.
5814bool isLayoutCompatible(ASTContext &C, EnumDecl *ED1, EnumDecl *ED2) {
5815  // C++11 [dcl.enum] p8:
5816  // Two enumeration types are layout-compatible if they have the same
5817  // underlying type.
5818  return ED1->isComplete() && ED2->isComplete() &&
5819         C.hasSameType(ED1->getIntegerType(), ED2->getIntegerType());
5820}
5821
5822/// \brief Check if two fields are layout-compatible.
5823bool isLayoutCompatible(ASTContext &C, FieldDecl *Field1, FieldDecl *Field2) {
5824  if (!isLayoutCompatible(C, Field1->getType(), Field2->getType()))
5825    return false;
5826
5827  if (Field1->isBitField() != Field2->isBitField())
5828    return false;
5829
5830  if (Field1->isBitField()) {
5831    // Make sure that the bit-fields are the same length.
5832    unsigned Bits1 = Field1->getBitWidthValue(C);
5833    unsigned Bits2 = Field2->getBitWidthValue(C);
5834
5835    if (Bits1 != Bits2)
5836      return false;
5837  }
5838
5839  return true;
5840}
5841
5842/// \brief Check if two standard-layout structs are layout-compatible.
5843/// (C++11 [class.mem] p17)
5844bool isLayoutCompatibleStruct(ASTContext &C,
5845                              RecordDecl *RD1,
5846                              RecordDecl *RD2) {
5847  // If both records are C++ classes, check that base classes match.
5848  if (const CXXRecordDecl *D1CXX = dyn_cast<CXXRecordDecl>(RD1)) {
5849    // If one of records is a CXXRecordDecl we are in C++ mode,
5850    // thus the other one is a CXXRecordDecl, too.
5851    const CXXRecordDecl *D2CXX = cast<CXXRecordDecl>(RD2);
5852    // Check number of base classes.
5853    if (D1CXX->getNumBases() != D2CXX->getNumBases())
5854      return false;
5855
5856    // Check the base classes.
5857    for (CXXRecordDecl::base_class_const_iterator
5858               Base1 = D1CXX->bases_begin(),
5859           BaseEnd1 = D1CXX->bases_end(),
5860              Base2 = D2CXX->bases_begin();
5861         Base1 != BaseEnd1;
5862         ++Base1, ++Base2) {
5863      if (!isLayoutCompatible(C, Base1->getType(), Base2->getType()))
5864        return false;
5865    }
5866  } else if (const CXXRecordDecl *D2CXX = dyn_cast<CXXRecordDecl>(RD2)) {
5867    // If only RD2 is a C++ class, it should have zero base classes.
5868    if (D2CXX->getNumBases() > 0)
5869      return false;
5870  }
5871
5872  // Check the fields.
5873  RecordDecl::field_iterator Field2 = RD2->field_begin(),
5874                             Field2End = RD2->field_end(),
5875                             Field1 = RD1->field_begin(),
5876                             Field1End = RD1->field_end();
5877  for ( ; Field1 != Field1End && Field2 != Field2End; ++Field1, ++Field2) {
5878    if (!isLayoutCompatible(C, *Field1, *Field2))
5879      return false;
5880  }
5881  if (Field1 != Field1End || Field2 != Field2End)
5882    return false;
5883
5884  return true;
5885}
5886
5887/// \brief Check if two standard-layout unions are layout-compatible.
5888/// (C++11 [class.mem] p18)
5889bool isLayoutCompatibleUnion(ASTContext &C,
5890                             RecordDecl *RD1,
5891                             RecordDecl *RD2) {
5892  llvm::SmallPtrSet<FieldDecl *, 8> UnmatchedFields;
5893  for (RecordDecl::field_iterator Field2 = RD2->field_begin(),
5894                                  Field2End = RD2->field_end();
5895       Field2 != Field2End; ++Field2) {
5896    UnmatchedFields.insert(*Field2);
5897  }
5898
5899  for (RecordDecl::field_iterator Field1 = RD1->field_begin(),
5900                                  Field1End = RD1->field_end();
5901       Field1 != Field1End; ++Field1) {
5902    llvm::SmallPtrSet<FieldDecl *, 8>::iterator
5903        I = UnmatchedFields.begin(),
5904        E = UnmatchedFields.end();
5905
5906    for ( ; I != E; ++I) {
5907      if (isLayoutCompatible(C, *Field1, *I)) {
5908        bool Result = UnmatchedFields.erase(*I);
5909        (void) Result;
5910        assert(Result);
5911        break;
5912      }
5913    }
5914    if (I == E)
5915      return false;
5916  }
5917
5918  return UnmatchedFields.empty();
5919}
5920
5921bool isLayoutCompatible(ASTContext &C, RecordDecl *RD1, RecordDecl *RD2) {
5922  if (RD1->isUnion() != RD2->isUnion())
5923    return false;
5924
5925  if (RD1->isUnion())
5926    return isLayoutCompatibleUnion(C, RD1, RD2);
5927  else
5928    return isLayoutCompatibleStruct(C, RD1, RD2);
5929}
5930
5931/// \brief Check if two types are layout-compatible in C++11 sense.
5932bool isLayoutCompatible(ASTContext &C, QualType T1, QualType T2) {
5933  if (T1.isNull() || T2.isNull())
5934    return false;
5935
5936  // C++11 [basic.types] p11:
5937  // If two types T1 and T2 are the same type, then T1 and T2 are
5938  // layout-compatible types.
5939  if (C.hasSameType(T1, T2))
5940    return true;
5941
5942  T1 = T1.getCanonicalType().getUnqualifiedType();
5943  T2 = T2.getCanonicalType().getUnqualifiedType();
5944
5945  const Type::TypeClass TC1 = T1->getTypeClass();
5946  const Type::TypeClass TC2 = T2->getTypeClass();
5947
5948  if (TC1 != TC2)
5949    return false;
5950
5951  if (TC1 == Type::Enum) {
5952    return isLayoutCompatible(C,
5953                              cast<EnumType>(T1)->getDecl(),
5954                              cast<EnumType>(T2)->getDecl());
5955  } else if (TC1 == Type::Record) {
5956    if (!T1->isStandardLayoutType() || !T2->isStandardLayoutType())
5957      return false;
5958
5959    return isLayoutCompatible(C,
5960                              cast<RecordType>(T1)->getDecl(),
5961                              cast<RecordType>(T2)->getDecl());
5962  }
5963
5964  return false;
5965}
5966}
5967
5968//===--- CHECK: pointer_with_type_tag attribute: datatypes should match ----//
5969
5970namespace {
5971/// \brief Given a type tag expression find the type tag itself.
5972///
5973/// \param TypeExpr Type tag expression, as it appears in user's code.
5974///
5975/// \param VD Declaration of an identifier that appears in a type tag.
5976///
5977/// \param MagicValue Type tag magic value.
5978bool FindTypeTagExpr(const Expr *TypeExpr, const ASTContext &Ctx,
5979                     const ValueDecl **VD, uint64_t *MagicValue) {
5980  while(true) {
5981    if (!TypeExpr)
5982      return false;
5983
5984    TypeExpr = TypeExpr->IgnoreParenImpCasts()->IgnoreParenCasts();
5985
5986    switch (TypeExpr->getStmtClass()) {
5987    case Stmt::UnaryOperatorClass: {
5988      const UnaryOperator *UO = cast<UnaryOperator>(TypeExpr);
5989      if (UO->getOpcode() == UO_AddrOf || UO->getOpcode() == UO_Deref) {
5990        TypeExpr = UO->getSubExpr();
5991        continue;
5992      }
5993      return false;
5994    }
5995
5996    case Stmt::DeclRefExprClass: {
5997      const DeclRefExpr *DRE = cast<DeclRefExpr>(TypeExpr);
5998      *VD = DRE->getDecl();
5999      return true;
6000    }
6001
6002    case Stmt::IntegerLiteralClass: {
6003      const IntegerLiteral *IL = cast<IntegerLiteral>(TypeExpr);
6004      llvm::APInt MagicValueAPInt = IL->getValue();
6005      if (MagicValueAPInt.getActiveBits() <= 64) {
6006        *MagicValue = MagicValueAPInt.getZExtValue();
6007        return true;
6008      } else
6009        return false;
6010    }
6011
6012    case Stmt::BinaryConditionalOperatorClass:
6013    case Stmt::ConditionalOperatorClass: {
6014      const AbstractConditionalOperator *ACO =
6015          cast<AbstractConditionalOperator>(TypeExpr);
6016      bool Result;
6017      if (ACO->getCond()->EvaluateAsBooleanCondition(Result, Ctx)) {
6018        if (Result)
6019          TypeExpr = ACO->getTrueExpr();
6020        else
6021          TypeExpr = ACO->getFalseExpr();
6022        continue;
6023      }
6024      return false;
6025    }
6026
6027    case Stmt::BinaryOperatorClass: {
6028      const BinaryOperator *BO = cast<BinaryOperator>(TypeExpr);
6029      if (BO->getOpcode() == BO_Comma) {
6030        TypeExpr = BO->getRHS();
6031        continue;
6032      }
6033      return false;
6034    }
6035
6036    default:
6037      return false;
6038    }
6039  }
6040}
6041
6042/// \brief Retrieve the C type corresponding to type tag TypeExpr.
6043///
6044/// \param TypeExpr Expression that specifies a type tag.
6045///
6046/// \param MagicValues Registered magic values.
6047///
6048/// \param FoundWrongKind Set to true if a type tag was found, but of a wrong
6049///        kind.
6050///
6051/// \param TypeInfo Information about the corresponding C type.
6052///
6053/// \returns true if the corresponding C type was found.
6054bool GetMatchingCType(
6055        const IdentifierInfo *ArgumentKind,
6056        const Expr *TypeExpr, const ASTContext &Ctx,
6057        const llvm::DenseMap<Sema::TypeTagMagicValue,
6058                             Sema::TypeTagData> *MagicValues,
6059        bool &FoundWrongKind,
6060        Sema::TypeTagData &TypeInfo) {
6061  FoundWrongKind = false;
6062
6063  // Variable declaration that has type_tag_for_datatype attribute.
6064  const ValueDecl *VD = NULL;
6065
6066  uint64_t MagicValue;
6067
6068  if (!FindTypeTagExpr(TypeExpr, Ctx, &VD, &MagicValue))
6069    return false;
6070
6071  if (VD) {
6072    for (specific_attr_iterator<TypeTagForDatatypeAttr>
6073             I = VD->specific_attr_begin<TypeTagForDatatypeAttr>(),
6074             E = VD->specific_attr_end<TypeTagForDatatypeAttr>();
6075         I != E; ++I) {
6076      if (I->getArgumentKind() != ArgumentKind) {
6077        FoundWrongKind = true;
6078        return false;
6079      }
6080      TypeInfo.Type = I->getMatchingCType();
6081      TypeInfo.LayoutCompatible = I->getLayoutCompatible();
6082      TypeInfo.MustBeNull = I->getMustBeNull();
6083      return true;
6084    }
6085    return false;
6086  }
6087
6088  if (!MagicValues)
6089    return false;
6090
6091  llvm::DenseMap<Sema::TypeTagMagicValue,
6092                 Sema::TypeTagData>::const_iterator I =
6093      MagicValues->find(std::make_pair(ArgumentKind, MagicValue));
6094  if (I == MagicValues->end())
6095    return false;
6096
6097  TypeInfo = I->second;
6098  return true;
6099}
6100} // unnamed namespace
6101
6102void Sema::RegisterTypeTagForDatatype(const IdentifierInfo *ArgumentKind,
6103                                      uint64_t MagicValue, QualType Type,
6104                                      bool LayoutCompatible,
6105                                      bool MustBeNull) {
6106  if (!TypeTagForDatatypeMagicValues)
6107    TypeTagForDatatypeMagicValues.reset(
6108        new llvm::DenseMap<TypeTagMagicValue, TypeTagData>);
6109
6110  TypeTagMagicValue Magic(ArgumentKind, MagicValue);
6111  (*TypeTagForDatatypeMagicValues)[Magic] =
6112      TypeTagData(Type, LayoutCompatible, MustBeNull);
6113}
6114
6115namespace {
6116bool IsSameCharType(QualType T1, QualType T2) {
6117  const BuiltinType *BT1 = T1->getAs<BuiltinType>();
6118  if (!BT1)
6119    return false;
6120
6121  const BuiltinType *BT2 = T2->getAs<BuiltinType>();
6122  if (!BT2)
6123    return false;
6124
6125  BuiltinType::Kind T1Kind = BT1->getKind();
6126  BuiltinType::Kind T2Kind = BT2->getKind();
6127
6128  return (T1Kind == BuiltinType::SChar  && T2Kind == BuiltinType::Char_S) ||
6129         (T1Kind == BuiltinType::UChar  && T2Kind == BuiltinType::Char_U) ||
6130         (T1Kind == BuiltinType::Char_U && T2Kind == BuiltinType::UChar) ||
6131         (T1Kind == BuiltinType::Char_S && T2Kind == BuiltinType::SChar);
6132}
6133} // unnamed namespace
6134
6135void Sema::CheckArgumentWithTypeTag(const ArgumentWithTypeTagAttr *Attr,
6136                                    const Expr * const *ExprArgs) {
6137  const IdentifierInfo *ArgumentKind = Attr->getArgumentKind();
6138  bool IsPointerAttr = Attr->getIsPointer();
6139
6140  const Expr *TypeTagExpr = ExprArgs[Attr->getTypeTagIdx()];
6141  bool FoundWrongKind;
6142  TypeTagData TypeInfo;
6143  if (!GetMatchingCType(ArgumentKind, TypeTagExpr, Context,
6144                        TypeTagForDatatypeMagicValues.get(),
6145                        FoundWrongKind, TypeInfo)) {
6146    if (FoundWrongKind)
6147      Diag(TypeTagExpr->getExprLoc(),
6148           diag::warn_type_tag_for_datatype_wrong_kind)
6149        << TypeTagExpr->getSourceRange();
6150    return;
6151  }
6152
6153  const Expr *ArgumentExpr = ExprArgs[Attr->getArgumentIdx()];
6154  if (IsPointerAttr) {
6155    // Skip implicit cast of pointer to `void *' (as a function argument).
6156    if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(ArgumentExpr))
6157      if (ICE->getType()->isVoidPointerType())
6158        ArgumentExpr = ICE->getSubExpr();
6159  }
6160  QualType ArgumentType = ArgumentExpr->getType();
6161
6162  // Passing a `void*' pointer shouldn't trigger a warning.
6163  if (IsPointerAttr && ArgumentType->isVoidPointerType())
6164    return;
6165
6166  if (TypeInfo.MustBeNull) {
6167    // Type tag with matching void type requires a null pointer.
6168    if (!ArgumentExpr->isNullPointerConstant(Context,
6169                                             Expr::NPC_ValueDependentIsNotNull)) {
6170      Diag(ArgumentExpr->getExprLoc(),
6171           diag::warn_type_safety_null_pointer_required)
6172          << ArgumentKind->getName()
6173          << ArgumentExpr->getSourceRange()
6174          << TypeTagExpr->getSourceRange();
6175    }
6176    return;
6177  }
6178
6179  QualType RequiredType = TypeInfo.Type;
6180  if (IsPointerAttr)
6181    RequiredType = Context.getPointerType(RequiredType);
6182
6183  bool mismatch = false;
6184  if (!TypeInfo.LayoutCompatible) {
6185    mismatch = !Context.hasSameType(ArgumentType, RequiredType);
6186
6187    // C++11 [basic.fundamental] p1:
6188    // Plain char, signed char, and unsigned char are three distinct types.
6189    //
6190    // But we treat plain `char' as equivalent to `signed char' or `unsigned
6191    // char' depending on the current char signedness mode.
6192    if (mismatch)
6193      if ((IsPointerAttr && IsSameCharType(ArgumentType->getPointeeType(),
6194                                           RequiredType->getPointeeType())) ||
6195          (!IsPointerAttr && IsSameCharType(ArgumentType, RequiredType)))
6196        mismatch = false;
6197  } else
6198    if (IsPointerAttr)
6199      mismatch = !isLayoutCompatible(Context,
6200                                     ArgumentType->getPointeeType(),
6201                                     RequiredType->getPointeeType());
6202    else
6203      mismatch = !isLayoutCompatible(Context, ArgumentType, RequiredType);
6204
6205  if (mismatch)
6206    Diag(ArgumentExpr->getExprLoc(), diag::warn_type_safety_type_mismatch)
6207        << ArgumentType << ArgumentKind->getName()
6208        << TypeInfo.LayoutCompatible << RequiredType
6209        << ArgumentExpr->getSourceRange()
6210        << TypeTagExpr->getSourceRange();
6211}
6212